docs(kit): pin core 1.19.0; teach the public demo's module members

The pin moves from 6890a74 (1.17.0) to 69998ec (1.19.0, website#224),
past 1.18.0 (website#223). Both are the public demo (DEMO_MODE.md §10
step 3). The chapters were read again for both versions:

- Chapter 2: a new section on a public demo site, covering demoLocks in
  module.json, ctx.demoMode and api.onDemoSeed (1.18.0). The call count
  becomes twenty.
- Chapter 5: a paragraph on an event action's demoRefuses (1.19.0), and
  a line in the action listing.

The one other core change in the window (website#221) is a wording fix
on core's Teams panel and nothing a module sees. The template declares
none of the new members, so template/module.json's coreApi becomes
^1.19.0 for the equality check only.

Checks run at the new pin:
- checkCoreApi, links, rename sites and chapter paths all pass, and so
  do the script tests (10 and 11).
- The template's imports, build, externals and swagger checks pass.
- Tests pass: server 82, client 20.
- The template was loaded as `examplegame` into a real core at this ref
  through core's own loader, with DEMO_MODE unset and with it true, and
  it registered both times.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

book/02-website-module.md

@@ -147,8 +147,9 @@ statement of your dependencies, and it makes a test double for it — see
 
 ## What you register
 
-Nineteen calls, all synchronous and all listed in [§2.4][api]: fifteen
-registrations, the two lifecycle hooks, and the two identity-link hooks. Five of the
+Twenty calls, all synchronous and all listed in [§2.4][api]: fifteen
+registrations, the two lifecycle hooks, the two identity-link hooks, and the demo's
+seed hook. Five of the
 registrations are the event system's, and [chapter 5](05-events.md) has those. What
 is worth knowing is not their signatures but the model behind them.
 
@@ -537,6 +538,55 @@ api.onIdentityLinked(async ({ userId, provider, subject, displayName }) => {})
   module made from it is yours to keep or remove.
 - Neither hook can mint a session or change who is signed in.
 
+### On a public demo site
+
+A site can run as a public demo (`MODULE_API_VERSION` 1.18.0). Anybody signs in with
+published logins, nothing destructive is allowed, and the site is wiped and seeded
+again every couple of hours. It is the same image with one flag set,
+`DEMO_MODE=true`. Core locks its own routes; yours are yours to declare, and three
+members are for that. With the flag off none of them changes anything, except that
+`demoLocks` is still validated.
+
+```json
+"demoLocks": [
+  { "method": "PUT",    "path": "/admin/mygame/servers/:id" },
+  { "method": "DELETE", "path": "/admin/mygame/servers/:id" }
+]
+```
+
+(The template has no write routes, so this is a shape rather than one of its files.)
+
+- **`demoLocks` in `module.json` lists your write routes that the demo refuses.**
+  Core answers a match `403 { code: 'DEMO_LOCKED', message }` before your handler
+  runs, the same body it gives for its own locks, so the site's one toast explains
+  it. Writes only (`POST`, `PUT`, `PATCH`, `DELETE`), in your routers' own `:param`
+  syntax with an optional trailing `/*`, and under one of your declared `mounts`.
+  **It is validated on every boot, demo or not**, so a wrong entry fails on your
+  machine rather than only on the demo.
+- **`ctx.demoMode` is for a lock a route list cannot express**, one that depends on
+  what is in the request rather than which URL it went to. The Rust module refuses a
+  console command by its first word, and a plugin's config file by the plugin that
+  owns it. Check it in your handler and answer with the same `403` body. It is also
+  how you hide the rare read that must never be shown on a demo, such as a file
+  holding credentials; `demoLocks` takes writes only.
+- **`api.onDemoSeed(fn)` writes your rows into the demo's fresh database.** The seed
+  calls `fn(data, { accounts })`: `data` is your section of the fixture
+  (`modules.<id>`, with every `"$env:NAME"` string already replaced) and `accounts`
+  maps each demo username to its user id. Core never writes your tables. **Upsert,
+  never insert**: the seed may run more than once on one database, and core seeds
+  its own content only the first time but calls your hook on every run. A fixture section for a module with no hook fails the seed, and so does a
+  hook that throws.
+- **Lock at the server, never in the UI.** A request sent with `curl`, or from an
+  old app build, must be refused exactly like a click. Your pages may explain a lock;
+  they must not hide or disable a control as the way of locking it.
+- **Declaring `demoLocks` needs `coreApi` `^1.18.0`**, because an older core rejects
+  the unknown key. Using only the other two should declare it as well: an older core
+  has no `onDemoSeed`, and its `ctx.demoMode` is `undefined`, which reads as "not a
+  demo".
+
+An event step the demo should refuse when it is saved is
+[chapter 5](05-events.md)'s `demoRefuses`.
+
 ## The schema fragment
 
 `template/server/db/schema.sql` is your tables. It is replayed **in full, at every

book/05-events.md

@@ -150,6 +150,7 @@ api.registerEventActions([{
   async revert({ runId, resources, idempotencyKey }) {},    // required iff 'ledger'
   async reconcile({ runId, resources }) {},                 // optional
   async progress({ runId, stepId, idempotencyKey, params, resources, viewer }) {}, // optional, 1.12.0
+  async demoRefuses(params) {},                             // optional, 1.19.0
 }])
 ```
 
@@ -189,6 +190,22 @@ event's public page and in the app.
   already cache, not from a fresh round trip to the game per reader.
 - **Failure.** A throw or a late answer costs a line, never the page.
 
+**`demoRefuses` keeps a step off a public demo** (MODULE_API 1.19.0). A demo site
+([chapter 2](02-website-module.md)) lets anybody author an event, and some steps must
+never be saved there: the Rust module refuses a console command that would stop the
+server. Core asks `demoRefuses(params)` only with `DEMO_MODE` on, for every step,
+when a definition is created, saved or published, with the step's checked params.
+
+- **The answer.** A sentence refuses the whole write with `403 DEMO_LOCKED`, and the
+  author reads it as written, so phrase it for them: *"quit" is turned off on the
+  demo site.* `null` lets the step through.
+- **It is a pure check.** No database, no game, nothing changed. A throw refuses too,
+  with core's own sentence, because a lock that cannot decide fails closed.
+- **Check again in `perform()`**, behind `ctx.demoMode`. A version published before
+  your list grew is never asked again, so the save cannot be the only lock.
+- **It needs `coreApi` `^1.19.0`.** An older core never asks it, and the save goes
+  through without a word.
+
 **`example` is required on every param, optional ones included.** It is the
 authoring form's placeholder. It is one word at declaration time and it is
 unreconstructable afterwards by anybody who did not write the action.

ci/core-ref.json

@@ -1,10 +1,23 @@
 {
   "repo": "https://gitea.whitlocktech.com/RunicGateway/website.git",
   "branch": "main",
-  "ref": "6890a74c7c4ad5690509e8c163e477d7f7b399e7",
+  "ref": "69998ec54854d46681def92985a2b299ee3582a6",
   "why": [
     "The core this kit is written against, pinned to a commit rather than a branch.",
     "",
+    "2026-10-26: moved from 6890a74 (1.17.0) to 69998ec (1.19.0, website#224),",
+    "past 1.18.0 (website#223). Both are the public demo (DEMO_MODE.md), and the",
+    "chapters were read again for both versions:",
+    "- 1.18.0: demoLocks in module.json, ctx.demoMode and api.onDemoSeed",
+    "  (chapter 2 gains a section, and its call count becomes twenty);",
+    "- 1.19.0: an event action's demoRefuses (chapter 5, a paragraph and a line",
+    "  in the action listing).",
+    "The one other core change in the window (website#221) is a wording fix on",
+    "core's Teams panel and nothing a module sees. The template declares none of",
+    "the new members, so nothing it does changed meaning; module.json's coreApi",
+    "becomes ^1.19.0 for the equality check. The real core run was repeated at",
+    "this ref, with the template as the only module in the directory.",
+    "",
     "2026-10-23: moved from 0a37a44 (1.12.0) to 6890a74 (1.17.0, website#220,",
     "the cutover that brought Steam sign-in and the Rust last fixes to `main`),",
     "past 1.13.0 to 1.16.0, which reached `main` together on 2026-10-22. The",

template/module.json

@@ -2,7 +2,7 @@
   "id": "examplegame",
   "name": "Example Game",
   "version": "0.1.0",
-  "coreApi": "^1.17.0",
+  "coreApi": "^1.19.0",
   "server": "server/index.js",
   "client": { "entry": "client/dist/entry.js" },
   "schema": "server/db/schema.sql",