docs(installer): add release orchestration and the bundle manifest

The installer needs CI that reacts when a component publishes a release. Adds
that as section 7, folded into version tracking because the bundle IS the compat
matrix -- which closes the "where does the compat matrix live" gap section 7
previously left open.

- 7.1 Bundle manifest: CI publishes an exact, protocol-checked combination of
  component versions; the installer resolves against it at run time and
  --bundle <tag> pins one. A link release regenerates JSON and leaves the
  installer binary untouched, so operators don't re-download the installer for a
  sidecar patch and the repo doesn't accumulate releases with identical code.
  Two compose-time gates: sidecar PROTOCOL_VERSION must equal the overlay
  manifest's declared version, and every asset's SHA256 must match.
- 7.2 Triggers: each component's release job POSTs to the installer's
  workflow-dispatch endpoint (link's release.yml already declares
  workflow_dispatch and already holds a write:repository token), plus a nightly
  cron so a missed dispatch self-heals. repository_dispatch avoided -- support
  is uncertain on this Gitea version.
- 7.3 Stale overlay: dispatch, don't wait. Components self-release on merge to
  their own main, so the release normally already exists. If main is ahead with
  *releasable* commits (docs:/chore: correctly cut nothing), fire that repo's
  workflow, compose from what exists now, warn loudly, and let the nightly fold
  in the result. Dispatching another repo's workflow is fine -- it still runs
  its own gates -- but polling it is not, since Gitea's dispatch endpoint
  returns no run handle.

Bundle CI becomes a Phase 0 deliverable, since Phase 1 resolves what to install
from the bundle. `update` now moves between checked combinations rather than two
independently-latest artifacts.

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

installer/PLAN.md

@@ -29,6 +29,7 @@ release/start scripts. The installer never writes a launcher.
 | Code signing | **Unsigned.** `SHA256SUMS` is the trust anchor; SmartScreen/Gatekeeper warnings are expected and documented, as with most self-hosted tooling |
 | Language | **Rust** — single static binary per OS, reuses the cross-compile pattern already proven in `link/.gitea/workflows/release.yml` |
 | Plugin source | **Release tarball artifact** — no git and no Gitea credentials on the shard host |
+| Composition | **Published bundle manifest** (§7.1). CI names an exact, protocol-checked combination of component versions; the installer fetches it at run time and `--bundle <tag>` pins one. Component releases regenerate JSON, not the installer binary |
 | Token handoff | **Print token + prefilled admin URL** at the end of the run |
 | Repo | **New repo**, `RunicGateway/installer`. It deploys *both* other components, so living inside `link/` would invert the dependency |
 | ServUO version | **Warn and skip.** Patches are verified against stock 57.4 only; on anything else the base install proceeds and the patch tier is skipped with a warning. Forks are the norm in a public audience — refusing outright would block most operators |
@@ -167,6 +168,9 @@ servuo-plugins v<ver>                 (new release, Phase 0)
 └── SHA256SUMS
 ```
 
+Binding those together is the **bundle manifest** (§7.1) — published by the installer repo's CI, not
+by any component, and the thing the installer actually resolves against.
+
 ```bash
 scp runicgateway-installer-linux-x86_64 user@server:/tmp/
 chmod +x runicgateway-installer-linux-x86_64
@@ -221,7 +225,10 @@ Repo work that must land before an installer can exist.
 2. **`link`: make the sidecar installable.** Confirm/settle default data paths, and add a way to
    read back config non-interactively (e.g. `--print-config` emitting JSON: bind addresses, token,
    protocol version, db path) so the installer does not have to scrape logs for the token.
-3. **Decide and document the compat matrix format** (§7).
+3. **Bundle CI in the installer repo** (§7). Compose job (read both repos' latest releases → run the
+   two gates → publish `bundle.json`), the nightly cron, and the dispatch step appended to each
+   component's release workflow. This must exist before Phase 1 is useful, since the installer
+   resolves what to install *from* the bundle.
 4. **`docs`: this file, plus `docs/installer/INSTALL.md`** (the operator-facing guide) once the
    shape is settled.
 
@@ -267,12 +274,16 @@ degrade loudly rather than silently.
 The last check matters most: it is the only thing that distinguishes "files copied" from "the bridge
 actually works" (§2.1).
 
-`runicgateway update` — asymmetric by component, deliberately:
+`runicgateway update` — resolves the current bundle (§7.1), then acts asymmetrically by component,
+deliberately:
 
-- **uo-link**: query the Gitea releases API → compare versions → download → verify checksum →
+- **uo-link**: compare the bundle's version against what is installed → download → verify checksum →
   replace binary → restart service.
-- **plugin overlay**: download the newer overlay tarball → verify → re-sync → record commit → tell
-  the operator ServUO must restart (the installer does not restart the shard).
+- **plugin overlay**: download the bundle's overlay tarball → verify → re-sync → record commit →
+  tell the operator ServUO must restart (the installer does not restart the shard).
+
+Because both come from one bundle, an update always moves to a combination whose protocol versions
+were checked together, rather than to two independently-latest artifacts that may disagree.
 
 `runicgateway uninstall` — **removes only what it exclusively owns, and never edits the ServUO
 tree.** The installer cannot know what the operator has changed in those files since deployment, so
@@ -321,7 +332,7 @@ later without changing anything here.
 
 ---
 
-## 7. Version tracking and the compat matrix
+## 7. Version tracking, the bundle, and release orchestration
 
 Three components version independently, bound by a protocol contract:
 
@@ -329,13 +340,72 @@ Three components version independently, bound by a protocol contract:
   `X-UOLink-Version` on every response; a mismatch is rejected `409`.
 - **website** — stores an expected protocol version in `uoLinkConfig` (admin-managed).
 - **plugin overlay** — has no queryable version before ServUO boots. The overlay release
-  `manifest.json` declares it, and `install.json` records what was deployed. `doctor` compares the
-  recorded overlay protocol version against the sidecar's live one.
+  `manifest.json` declares it, and `install.json` records what was deployed.
 
-**Open risk:** the v3 cutover is mid-flight — protocol work landed on `edge` branches with the
-`edge → main` cutover still open across four repos. Until that lands, `main` and `edge` disagree
-about `PROTOCOL_VERSION`, so the installer must not hardcode a version anywhere; it reads what the
-artifacts declare. See `docs/link/v3.md`.
+### 7.1 The bundle manifest
+
+**The bundle is the compat matrix.** Rather than the installer hardcoding versions or blindly
+resolving "latest", CI publishes a small manifest naming an exact, checked combination:
+
+```json
+{
+  "bundle": "2026.08.01",
+  "protocol": 3,
+  "link":    { "version": "3.0.1", "sha256": "a91f..." },
+  "overlay": { "version": "2.4.0", "commit": "a81f42c", "sha256": "7c3e..." }
+}
+```
+
+The installer fetches the current bundle at run time; `--bundle <tag>` pins an older one for a
+reproducible install. Because the bundle is data, **a new `link` release regenerates ~20 lines of
+JSON and leaves the installer binary untouched** — operators do not re-download the installer to
+pick up a sidecar patch, and the installer does not accumulate releases whose code is byte-identical.
+
+Two gates run at compose time, both cheap and both worth it:
+
+1. The sidecar's `PROTOCOL_VERSION` must equal the overlay manifest's declared protocol version.
+   This is the check that catches an `edge`/`main` protocol mismatch before it reaches an operator.
+2. Every referenced asset must exist and its SHA256 must match the publishing repo's `SHA256SUMS`.
+
+### 7.2 What triggers a bundle
+
+| Trigger | Why |
+|---|---|
+| `link` publishes a release | Its release job `POST`s to the installer repo's workflow-dispatch endpoint as its final step. `link/.gitea/workflows/release.yml` already declares `workflow_dispatch: {}` and already holds a `write:repository` token |
+| `servuo-plugins` publishes a release | Same, once Phase 0 gives it a release workflow |
+| Nightly cron on the installer repo | Recomputes from whatever the latest releases actually are, so a missed or failed dispatch self-heals instead of silently pinning operators to a stale sidecar |
+
+`repository_dispatch` is deliberately avoided — support for it is uncertain on this Gitea version,
+whereas dispatching an existing `workflow_dispatch` workflow via the API works today.
+
+### 7.3 Stale-overlay handling: dispatch, don't wait
+
+Each component **self-releases on merge to its own `main`**, using the same conventional-commit
+engine. Note that "updated since the last release" must mean *releasable* commits — the engine sets
+`RELEASE=false` when nothing but `docs:`/`chore:` has landed, so a docs typo correctly does **not**
+cut an overlay release, and the bundle keeps using the existing one.
+
+So by the time the installer's CI looks, the release normally already exists. If it finds
+`servuo-plugins` main ahead of its latest release *with* releasable commits, it:
+
+1. fires that repo's release workflow via workflow-dispatch and **does not wait for it**,
+2. composes this bundle from the assets that exist right now,
+3. writes a loud warning into the job summary.
+
+The new overlay release lands minutes later on its own and the nightly cron folds it into the next
+bundle. This gets the automation without the flaky part: dispatching another repo's workflow is
+fine — that workflow still runs its own gates — but *polling* it is not, because Gitea's dispatch
+endpoint returns no run handle, so the job would have to guess which run is its own and hold a
+runner idle meanwhile. The warning exists so a genuinely broken release workflow surfaces once
+rather than being silently retriggered every night forever.
+
+### 7.4 Open risk
+
+The v3 cutover is mid-flight — protocol work landed on `edge` branches with the `edge → main`
+cutover still open across four repos. Until that lands, `main` and `edge` disagree about
+`PROTOCOL_VERSION`, so the installer must not hardcode a version anywhere; it reads what the
+artifacts declare, and §7.1's gate 1 is what stops a mismatched pair from being published as a
+bundle. See `docs/link/v3.md`.
 
 ---