docs(website): record the shard visibility framework

Protocol 3.0 Part A. Admin-configurable, per-feature and per-field
audience control over every shard-derived surface, replacing the static
PUBLIC_KINDS allowlist that used to be the whole boundary.

- SHARD_VISIBILITY.md (new): the admin-facing guide - the ladder, what
  each of the ten features exposes, the defaults, the two rules that are
  code rather than configuration, and worked examples.
- BACKEND_DESIGN.md 6.5 (new): the same thing as a security contract -
  the ladder and how viewerLevel resolves it, the locked acct/webId rule,
  the fail-closed kind map, the asymmetric ladder fallbacks, and the
  three enforcement points. Plus the shard_feature_visibility schema, the
  /public/shard/features route, and the adminOnly tier on
  /admin/shard/visibility.

Defaults reproduce pre-3.0 behavior everywhere, with one deliberate
exception which is the leak Part A was written to close: guilds and
governors previously returned the raw stored payload, whose leader and
governor actors carry acct and webId, to anonymous callers.

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -19,6 +19,7 @@ ci/        cross-cutting CI/quality notes
 | [BACKEND_DESIGN.md](website/BACKEND_DESIGN.md) | API contract, DB schema, security model |
 | [HERO_EDITOR.md](website/HERO_EDITOR.md) | Hero canvas editor feature spec |
 | [WIKI_UPGRADE.md](website/WIKI_UPGRADE.md) | Wiki subsystem upgrade notes |
+| [SHARD_VISIBILITY.md](website/SHARD_VISIBILITY.md) | Who sees which shard data — the admin-configurable audience framework |
 | [website-README.md](website/website-README.md) | Snapshot of the website repo's README (setup/run reference) |
 | [PROJECT_TREE.md](website/PROJECT_TREE.md) | Auto-generated snapshot of the repo's tracked file layout |
 

website/BACKEND_DESIGN.md

@@ -99,7 +99,7 @@ server/
                  pages.router.js        (2)  /public/pages — the draft-preview
                                              route precedes /:slug and is
                                              deliberately not site-mode gated
-                 shard.router.js       (12)  /public/shard/* incl. the anonymous
+                 shard.router.js       (13)  /public/shard/* incl. the anonymous
                                              SSE stream; never site-mode gated
                  site.router.js         (4)  /settings /status /version /contact —
                                              the group-root singletons; declares no
@@ -358,6 +358,19 @@ analogue to a password — and there is no hash-lookup constraint (verification
 unused rows and `bcrypt.compare`s each, like password verification). `used_at` is the single-use
 marker. Cleared wholesale on TOTP disable / password change / password reset.
 
+### shard_feature_visibility  — per-feature audience config (Protocol 3.0)
+
+One row per shard feature: `feature` (PK), `enabled`, `audience` (a rung on the ladder in §6.5),
+`stream` (whether the feature's kinds fan out over SSE at all), `field_rules` JSON (`{field: rung}`
+for the sensitive fields only), `updated_by`, `updated_at`.
+
+**An absent row means "use the compiled default", and the compiled defaults reproduce pre-3.0
+behavior — so an empty table is a no-op and there is nothing to seed.** Stored rows are merged over
+the defaults on read, which is also where the invariants are re-applied: a row naming an unknown
+feature is ignored (a stale row must not resurrect a removed feature), an invalid rung falls back to
+the default rather than failing open, and a rule touching a locked field (`acct` / `webId`) is
+discarded. See §6.5.
+
 ---
 
 ## 4. API contract
@@ -556,6 +569,7 @@ from the per-route **siteMode** middleware (§5), never from an auth gate.
 | GET | `/wiki` | list of pages (slug + title) |
 | GET | `/wiki/:slug` | single page |
 | POST | `/contact` | (rate-limited) send mail via SMTP; if unconfigured, respond `{fallback:"mailto", email}` |
+| GET | `/shard/features` | the shard features **this caller** may reach plus the audience rung they resolved to (§6.5), so a client hides nav it can't follow. Reports only what the caller can see — the list itself never discloses a gated feature. Consumed by the SPA header and (pending) the Android nav. |
 
 Public content GETs pass through the **siteMode** gate (§5).
 
@@ -570,6 +584,10 @@ the whole gate. The ops/config capabilities — `uo-link`, `email`, `discord-bot
 linking carries no extra gate and the in-game staff operations carry `modAccess`. There is no residual
 file: every admin route is declared in a capability router.
 
+`GET`/`PUT /admin/shard/visibility` are the third tier on that mixed prefix: **`adminOnly`**, because
+they decide what *anonymous* visitors can see (§6.5). They sit above `modAccess` deliberately — a
+moderator can ban a player but cannot decide what the public internet reads.
+
 `GET /dashboard` and `PUT /site-mode` are the one place where a **single screen spans two tiers**: the
 dashboard is staff-wide, but the site-mode toggle on it is `adminOnly`. The client must therefore gate
 that control on its own (`Dashboard.jsx` renders it only for `role === 'admin'`) rather than relying on
@@ -672,6 +690,56 @@ who"; `activity_log` provides the history feed.
 - **`app.set('trust proxy', 1)`** so secure cookies, `req.ip`, and rate-limiting work behind Pangolin.
 - **CORS**: same-origin in prod (SPA served by Express). Dev only: allow `CLIENT_ORIGIN` (Vite, `http://localhost:5173`) with `credentials:true`.
 
+### 6.5 Shard visibility — the audience boundary (Protocol 3.0)
+
+Every shard-derived surface is gated by an **admin-configurable, per-feature and per-field** audience
+setting. This **replaces** the static `PUBLIC_KINDS` allowlist that used to be the whole boundary.
+Policy lives in `utils/shardVisibility.js`; rows live in `shard_feature_visibility`; the admin surface
+is `GET`/`PUT /admin/shard/visibility` (`adminOnly`). Admin-facing guide:
+[`SHARD_VISIBILITY.md`](SHARD_VISIBILITY.md). Design: [`../link/v3.md`](../link/v3.md) §3.
+
+**The ladder.** `anonymous < logged_in < player < staff < admin`, each rung implying the ones below.
+`viewerLevel(req)` resolves it: no session ⇒ `anonymous`; authenticated ⇒ `logged_in`; authenticated
+with a linked game account ⇒ `player`; moderator ⇒ `staff`; admin ⇒ `admin`. **Staff satisfy the
+`player` rung without a linked account** (consistent with `/player/*` being role-agnostic).
+**`editor` gets no shard privilege** — it is a content role, and mapping it to `staff` would silently
+widen what editors see.
+
+**Two invariants that are code, not configuration.** Both are enforced server-side and both reject
+rather than silently ignore:
+
+1. **`acct` and `webId` are admin-only, always.** They are not exposed as configurable fields, and a
+   stored row attempting to loosen them is discarded on read as well as rejected on write. A character
+   name is visible in game; the account behind it and the website user it links to are not.
+2. **A kind absent from `KIND_FEATURE` is never broadcast below `admin`.** Fail closed. This is what
+   keeps the kind map a security boundary rather than a convenience filter, and it means a shard that
+   starts emitting an unknown event degrades to staff-only, never to public.
+
+**Fail-closed everywhere else too.** An unreadable visibility config withholds every public frame; a
+DB failure falls back to the compiled defaults (pre-3.0 behavior), not to open; an unresolvable viewer
+subscribes as `anonymous`. The ladder comparison uses **asymmetric** fallbacks by design — an unknown
+*viewer* level floors to the bottom rung and an unknown *requirement* ceils to admin, so an
+unrecognised value loses on both sides. (A single shared fallback cannot do that: whichever direction
+it picks, it fails open on one side.)
+
+**Three enforcement points, one config:**
+
+| Where | Mechanism |
+|---|---|
+| Routes | `requireFeature(name)` — **404** when the feature is disabled (don't leak that it exists), **403** when the caller is below its audience. `projectFeature` then strips out-of-rung fields from the body. |
+| SSE (`utils/shardBroadcast.js`) | Per-connection filtering. A subscriber's rung is resolved **once at subscribe time and frozen** for that connection, so a long-lived stream can't gain privilege; each frame is then mapped kind→feature, gated, and field-projected per viewer. Two subscribers can legitimately receive different versions of one event, or one of them nothing. |
+| Nav | `GET /public/shard/features` returns only what the caller may reach, so the SPA never renders a link that would 403. Presentation only. |
+
+Config reads are cached ~5s, so admin changes take effect within seconds **including on already-open
+streams**. `PUBLIC_KINDS` still exists and is still exported (`/feed` filtering, `notificationStreams.js`)
+but is now **derived** from the kind map rather than hand-maintained, so the two cannot drift.
+
+**Defaults reproduce pre-3.0 behavior exactly**, so installing the framework is a no-op until an admin
+changes something — with one deliberate exception, which is the leak it was written to close:
+`/public/shard/guilds` and `/public/shard/governors` previously returned the raw stored payload, whose
+`leader` / `governor` actors carry `acct` and `webId`. Those fields are now stripped for every caller
+below admin.
+
 ---
 
 ## 7. Email

website/SHARD_VISIBILITY.md

@@ -0,0 +1,124 @@
+# Shard visibility — who sees which shard data
+
+**Status:** Built (Protocol 3.0 Part A). Admin → Shard Visibility.
+**Audience:** shard owners and admins.
+**Companion to** [`../link/v3.md`](../link/v3.md) §3 (the design) and
+[`BACKEND_DESIGN.md`](BACKEND_DESIGN.md) §6 (the security contract).
+
+The website surfaces a lot of live shard data. What your players, your staff and the anonymous
+internet may each see is **yours to decide**, per feature, from Admin → Shard Visibility.
+
+Nothing changes until you change it: every setting ships at the value that reproduces how the site
+behaved before this panel existed.
+
+---
+
+## 1. The audience ladder
+
+Five rungs. Each one includes everyone below it.
+
+| Rung | In the UI | Who that is |
+|---|---|---|
+| `anonymous` | **Everyone** | Anyone at all, signed in or not. |
+| `logged_in` | **Signed in** | Any registered account, whether or not they've linked a game account. |
+| `player` | **Linked players** | Accounts with a linked in-game account. **Staff always qualify**, linked or not. |
+| `staff` | **Staff** | Admins and moderators. |
+| `admin` | **Admins only** | Admins. |
+
+Two notes that surprise people:
+
+- **`editor` is a content role, not a shard role.** Editors write news and wiki pages; they get no
+  shard privilege from that. An editor is treated by link status like any other member. This matches
+  the rest of the site, where shard staff powers are admin-or-moderator.
+- **Staff satisfy `player` without linking.** Otherwise an admin would be locked out of surfaces
+  they'd gated to players, which is how the `/player/*` routes already behave.
+
+## 2. What you can set per feature
+
+**Enabled.** Off means gone. The feature's pages return “not found”, not “forbidden” — a disabled
+feature doesn't advertise that it exists.
+
+**Who can see it.** The minimum rung, from the ladder above.
+
+**Live updates.** Whether this feature pushes changes to open pages in real time. Turning it off
+doesn't break the page; it just refreshes on load instead of updating in place.
+
+**Sensitive fields.** Some features expose a field that deserves its own rung — you can publish the
+board while holding back one column. See the table in §3.
+
+## 3. The features, and their defaults
+
+| Feature | What it exposes | Default | Sensitive fields |
+|---|---|---|---|
+| **Shard status** | Connection state, online count, gold-supply series | Everyone | — |
+| **Activity feed** | Deaths, kills, skill gains, quests, logins | Everyone | — |
+| **Champion spawns** | The live champion / mini-champ / sea-boss board | Everyone | — |
+| **Guilds** | Guild rosters, alliances, leaders | Everyone | — |
+| **Town governors** | City Loyalty governors, elections, term history | Everyone | — |
+| **Houses / IDOC** | Houses in danger | Everyone | House owner → Staff · House price → Staff |
+| **Players online** | Population aggregate, staff-online widget | Everyone | In-game location → Staff |
+| **Shard rules** | Skill/stat caps, house limits, vet rewards, the ruleset | Everyone | Connect address → Everyone |
+| **Spawn atlas** | Bestiary and spawn locations (static content) | Everyone | — |
+| **Leaderboards** | Point and loyalty standings | Everyone | Character names → Everyone |
+| **Marketplace** | The shard-wide player-vendor index | Everyone, **live updates off** | Vendor owner name → Everyone · Location → Everyone |
+
+**Why the marketplace ships with live updates off.** A live feed of every vendor's full inventory
+would be the single largest thing the site sends. No page needs it — the marketplace is a search over
+stored data with a “prices last refreshed N minutes ago” stamp. Turn it on only if you want it.
+
+**Why house owner/price default to Staff.** The public Houses page has always been a "where are the
+falling houses" board — location only. Owner and price are the staff view. That split is preserved.
+
+## 4. What you cannot change
+
+Two rules are enforced in code and are not settings. Attempting to set them returns an error rather
+than silently ignoring you.
+
+**1. Game account names and website user ids are admin-only, always.**
+`acct` and `webId` never appear below the admin rung on any surface. A character *name* is visible in
+game to anyone standing next to them; the **account** behind it is not, and neither is the website
+user it's linked to. Publishing those would disclose something the shard itself doesn't, and would
+tie a player's in-game identity to their forum identity without their consent.
+
+**2. Unknown event kinds are never broadcast below admin.**
+The live stream maps each event kind to a feature. A kind with no mapping — a new event from a shard
+plugin the site doesn't know yet, say — goes to admins only. It fails closed. This is what keeps the
+stream safe by default when the shard starts sending something new: the worst case is that staff see
+it and players don't, never the reverse.
+
+## 5. How it's enforced
+
+Three places, one config:
+
+- **Page and API requests** are checked before the handler runs, and the response is then stripped of
+  any field above the caller's rung.
+- **The live stream** resolves a viewer's rung once, when they connect, and freezes it for that
+  connection — a long-open page can't gain privilege because something changed underneath it. Each
+  event is then gated and stripped per viewer, so two people watching the same page can legitimately
+  receive different versions of the same event, or one of them nothing.
+- **Navigation** hides links a viewer can't follow, so they don't hit a wall. This is presentation
+  only — the gate is server-side either way.
+
+Changes take effect within about five seconds, **including on streams that are already open**. You
+don't need to restart anything.
+
+If the database is briefly unreachable, the site falls back to the built-in defaults — the pre-v3
+behavior — rather than to "everything is public".
+
+## 6. Worked examples
+
+**"I want a private shard — nothing public until people register."**
+Set every feature to **Signed in**. Anonymous visitors still get the site itself; the shard data
+disappears from the nav.
+
+**"Publish the market, but don't tie vendors to players."**
+Marketplace → Everyone, with **Vendor owner name** → Staff. Prices, items and locations stay public;
+who owns each vendor doesn't.
+
+**"Leaderboards for members only."**
+Leaderboards → **Linked players**. Anyone who's linked a game account sees the standings; drive-by
+visitors don't.
+
+**"Let players see house owners."**
+Houses → Everyone, **House owner** → Linked players. Note this is a real disclosure: house ownership
+is visible in game, but the website makes it searchable in a way the game doesn't.