feat: the module skeleton and every bundle seam

module-rust, id 'rust', built from the Integration Kit's template. Phase 1's job
is the kit's own argument: get every seam working at once with almost nothing in
them, so that afterwards you break exactly one at a time.

What is here:

* /rust on all three tiers, because the loader holds module.json's mounts against
  what is registered in BOTH directions -- so the declaration and the
  registration land together or not at all. The player tier is honestly thin: it
  answers the server list on the authenticated tier, delegating to the same model
  the public tier uses so the two cannot drift while they are meant to be the
  same. It is the address the app will call, registered now rather than moved
  later.
* Two tables. rust_servers is configuration an operator writes; rust_server_state
  is what a sidecar reported. Separate tables because they have different
  writers, lifetimes and audiences -- and because purging observed state while
  keeping the configuration is a thing an operator will want.
* Per-server sidecar tokens through ctx.secretBox, write-only in the API. The
  admin list reports hasToken and never the credential, and an empty token on a
  save leaves the stored one alone -- a form that posts its own blank field would
  otherwise erase a credential every time somebody renamed a server.
* A real sidecar client. It never throws: every call answers {ok, status, data},
  and the status is what tells a wrong URL from a wrong token from a mismatched
  protocol -- all three present as 'the site says my server is offline' and each
  has a different fix.
* The five guards, green: check:imports, check:swagger, check:externals, and both
  suites.

What is deliberately NOT registered: the Team provider, triggers, audiences,
engagement seeds, notification streams, the four event catalogues, and the two
extension slots. Each arrives with the phase that has something real to put in
it, and a test asserts their absence so that removing it is deliberate. A
declared trigger nothing emits and a declared slot nothing fills are both
surfaces an operator can configure and then wait on, which is worse than an
absent one because the absence is visible.

Two corrections to the kit's template, both feedback for a later phase:

* registration.test.js read one page BY NAME to check declared slots are
  rendered, so a module declaring none dies on ENOENT before reaching the loop
  that would have been empty. It now scans every file under src/routes.
* test/_fakes.js supplied validator: {}. An admin router that builds validation
  chains at file scope cannot be required with that, so the fake holds the real
  express-validator -- for the same reason it holds a real express Router.

The kit was right about noGameConnection.test.js: its header predicts that a
module adding a sidecar client will see the check go red, names sidecarClient.js
as the file to allow, and says narrow it rather than delete it. That is exactly
what happened on the first run, and the fix was the one line the header names.

Installed into a real core and verified: the module reaches 'started', publishes
its capability, serves its chunk, and renders a server whose server.hello
originated in a live Rust server.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016wDDVXWMDz82WqE1i969r4

server/test/schema.test.js

@@ -0,0 +1,116 @@
+// ── The schema fragment, checked against §2.6's rules ─────────────────────
+//
+// Core validates the fragment at LOAD time and refuses to mount a module that
+// breaks a rule — with no tables created and no routes served. That is the right
+// behaviour and a slow way to find a typo, so the same rules are checked here.
+//
+// **This is also the suite that catches a half-finished rename.** Change the id
+// in `module.json` and forget a table name, and the prefix assertion below fails
+// immediately rather than at an operator's first boot.
+
+const test = require('node:test')
+const assert = require('node:assert')
+const fs = require('node:fs')
+const path = require('node:path')
+
+const manifest = require('../../module.json')
+
+const read = (rel) => fs.readFileSync(path.resolve(__dirname, '..', '..', rel), 'utf8')
+
+/**
+ * Split a SQL file into statements the way core does.
+ *
+ * Core's own splitter is shared code (`utils/sqlStatements.js`) used by both the
+ * loader and the schema replay — this is a small stand-in for a test, and it is
+ * deliberately simple because the fragment it reads is deliberately simple. If
+ * your schema grows a stored procedure or a string containing a semicolon, stop
+ * trusting this and read the fragment a different way.
+ */
+function statements(sql) {
+  return sql
+    .split('\n')
+    .filter((line) => !line.trim().startsWith('--'))
+    .join('\n')
+    .split(';')
+    .map((s) => s.trim())
+    .filter(Boolean)
+}
+
+const schema = statements(read(manifest.schema))
+const purge = statements(read(manifest.purge))
+
+// The allowlist core enforces. Note it is an ALLOWLIST and not a `DROP` denylist:
+// this file replays on every boot, so TRUNCATE or DELETE would empty a table on
+// every restart — which no denylist naming only DROP would have caught.
+const ALLOWED_VERBS = ['CREATE', 'ALTER', 'INSERT', 'UPDATE']
+
+test('every statement starts with an allowed verb', () => {
+  for (const statement of schema) {
+    const verb = statement.split(/\s+/)[0].toUpperCase()
+    assert.ok(ALLOWED_VERBS.includes(verb), `"${verb}" is not one of ${ALLOWED_VERBS.join(', ')}`)
+  }
+})
+
+test('every table is prefixed with the module id', () => {
+  for (const statement of schema) {
+    const match = /^CREATE\s+TABLE(?:\s+IF\s+NOT\s+EXISTS)?\s+`?([A-Za-z0-9_]+)`?/i.exec(statement)
+    if (!match) continue
+    assert.ok(
+      match[1].startsWith(`${manifest.id}_`),
+      `table "${match[1]}" is not prefixed "${manifest.id}_" — core will refuse to load this module`,
+    )
+  }
+})
+
+test('the fragment is idempotent — it replays on every boot', () => {
+  for (const statement of schema) {
+    if (/^CREATE\s+TABLE/i.test(statement)) {
+      assert.match(statement, /IF\s+NOT\s+EXISTS/i, 'CREATE TABLE without IF NOT EXISTS')
+    }
+    if (/^ALTER\s+TABLE/i.test(statement) && /ADD\s+COLUMN/i.test(statement)) {
+      assert.match(statement, /IF\s+NOT\s+EXISTS/i, 'ADD COLUMN without IF NOT EXISTS')
+    }
+    if (/^INSERT\s+INTO/i.test(statement)) {
+      // A plain INSERT succeeds once and then fails the whole replay on the next
+      // boot with a duplicate key — the classic "worked until I restarted it".
+      assert.ok(
+        /INSERT\s+IGNORE/i.test(statement) || /ON\s+DUPLICATE\s+KEY/i.test(statement),
+        'INSERT must be IGNORE or carry ON DUPLICATE KEY — it runs again every boot',
+      )
+    }
+  }
+})
+
+test('purge drops every table the schema creates', () => {
+  const created = schema
+    .map((s) => /^CREATE\s+TABLE(?:\s+IF\s+NOT\s+EXISTS)?\s+`?([A-Za-z0-9_]+)`?/i.exec(s))
+    .filter(Boolean)
+    .map((m) => m[1])
+  const dropped = purge
+    .map((s) => /^DROP\s+TABLE(?:\s+IF\s+EXISTS)?\s+`?([A-Za-z0-9_]+)`?/i.exec(s))
+    .filter(Boolean)
+    .map((m) => m[1])
+
+  for (const table of created) {
+    assert.ok(dropped.includes(table), `${table} is created but never dropped — purge would orphan it`)
+  }
+  for (const table of dropped) {
+    assert.ok(created.includes(table), `${table} is dropped but never created`)
+  }
+})
+
+test('purge drops in the reverse of creation order', () => {
+  // With one table this proves nothing; with a parent and its children it is the
+  // difference between a clean teardown and a purge that fails halfway, leaving
+  // exactly the orphaned data it exists to remove.
+  const created = schema
+    .map((s) => /^CREATE\s+TABLE(?:\s+IF\s+NOT\s+EXISTS)?\s+`?([A-Za-z0-9_]+)`?/i.exec(s))
+    .filter(Boolean)
+    .map((m) => m[1])
+  const dropped = purge
+    .map((s) => /^DROP\s+TABLE(?:\s+IF\s+EXISTS)?\s+`?([A-Za-z0-9_]+)`?/i.exec(s))
+    .filter(Boolean)
+    .map((m) => m[1])
+
+  assert.deepStrictEqual(dropped, [...created].reverse())
+})