feat(modules): install, uninstall, purge and restart (phase 4, slice 1)

The consumer half of a release module-uo's CI has been publishing since
phase 3 closed. Before this, core had the installed_modules provenance
columns and no code that could ever fill them: nothing fetched, verified,
unpacked, removed or purged anything, and there was no admin route at all.

Adds modules/archive.js, modules/install.js, schema.runPurge(),
lifecycle.stop(), loader.stopHook(), and /api/v1/admin/modules with eight
routes. 797 server tests (+76), manifest 158 -> 166 + 2 internal, OpenAPI
gains 8 operations and loses nothing.

Reject, never sanitise
----------------------
The download is the easy part: an https-only allowlist re-checked on every
redirect hop, a declared sha256 compared against the bytes that arrived, and
a byte cap. Unpacking is where the archive chooses the filenames, and core
writes into a directory bind-mounted from the host, so an escape is not
confined to the container.

archive.js inspects the whole archive before a byte is unpacked and refuses
absolute and drive-absolute paths, `..` segments, NUL bytes, backslashes,
anything that is not a regular file or a directory, more than one top-level
entry, and anything over the entry or byte caps. Refusing symlinks and
hardlinks outright is what keeps this off the majority of node-tar's
published advisories rather than depending on the library to contain them.

That two-pass shape is load-bearing, and it was measured rather than assumed:
extracting an archive whose fourth member escapes upward throws under
node-tar 7.5.22 -- and leaves the first three members on disk. The loader
scans that directory at require time on the next boot, so a half-unpacked
module is a module. Everything therefore happens in a scratch directory that
is removed on any failure, and the move into place is the last step.

`tar` is pinned to ^7.5.22 rather than the ^6 that installs by default: 6.x
is flagged critical, and reading the advisory list is what the file's header
now says out loud -- almost all of it is hardlink or symlink traversal and
PAX header interpretation differentials, which is exactly this feature's
threat model.

Two things the plan had wrong
-----------------------------
The bundle's top-level directory is `module-uo-<version>`, not the module id
-- so "the top-level name must equal the id" was checked against nothing real.
The extractor strips that level instead, because its name belongs to whoever
published the bundle and the directory it lands in is core's. What is checked
instead is the unpacked module.json: a manifest promising `uo` and delivering
something else is refused rather than installed under the name it promised.

And purge cannot be a follow-up action (decision 5): purge.sql lives inside
the directory uninstall deletes. It is offered in the uninstall flow and as a
standalone action on a still-installed module, and the standalone one refuses
unless the module is already disabled -- dropping tables under something that
is still serving leaves it answering out of a world that no longer exists.

Disable now means stopped
-------------------------
lifecycle.stop() dispatches that one module's onShutdown before flipping the
guard, so a module an operator switches off actually releases its sockets and
closes its streams instead of merely becoming unreachable. The hook runs
first and the state moves after it, because while onShutdown runs the module
is still `started` and that is the only state in which its routes and the
world it is tearing down agree. A hook that throws does not stop the disable
-- the opposite of the boot path's rule, and deliberately.

Enable is not its mirror and there is no start(id) beside it. There is no
onBoot re-dispatch and the hooks were never promised re-entrant, so enable
moves the row and the restart route starts it. A test pins that enable does
not touch the loader, because "fixing" it is a one-line change that would put
a module with closed sockets back on the nav.

Restart raises SIGTERM against its own process rather than calling the
shutdown path directly, so server.js's handler stays the one graceful-shutdown
path and this route cannot drift from it.

The allowlist bootstraps from MODULE_SOURCE_HOSTS into a settings row and is
admin-managed after that (decision 6); seedDefault is INSERT IGNORE, so
changing the variable on an existing deployment is a no-op by design. An empty
list forbids every install rather than allowing every host -- the safe
direction for a value someone might blank by accident.

Verified against the real v0.3.0 release
----------------------------------------
Not a fixture: fetched the published install manifest over the real Gitea
host and its redirect chain, verified the sha256, inspected and unpacked the
252,517-byte artifact to 82 files, and then booted core against the result --
the module registered its five mounts, seven streams and eight capabilities
and resolved its client chunk, with no scratch directory left behind.

Two defects this slice's own tooling caught, both of which had already been
written down as classes:
  - the controller destructured runPurge at require time, capturing the
    function rather than the module, which made the one dependency whose
    ORDER matters the one that could not be substituted;
  - two swagger annotations carried an apostrophe inside a quoted string,
    dropped silently by swagger-autogen before slice 5 taught it to fail loudly.

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

server/test/moduleLifecycle.test.js

@@ -125,6 +125,11 @@ function fakeModel(seed = []) {
       if (!row || row.state === 'disabled') return
       Object.assign(row, { state: 'startup_failed', failureStage: stage, failureReason: reason })
     },
+    async disable(id) {
+      calls.push(`disable:${id}`)
+      const row = rows.get(id)
+      if (row) Object.assign(row, { state: 'disabled', failureStage: null, failureReason: null })
+    },
   }
   return model
 }
@@ -374,3 +379,151 @@ test('a hook that throws does not stop the ones behind it', async () => {
   await assert.doesNotReject(() => lifecycle.shutdown({ modules: loader }))
   assert.deepEqual(noted(file), ['shutdown:zzz', 'shutdown:aaa'])
 })
+
+// ── stop(): the admin panel's Disable ──────────────────────────────────────
+//
+// Phase 4, §2.7.2 decision 3. Phase 2's disable moved a record and left the
+// module running; the whole point of these tests is that it no longer does.
+
+test('stop runs that one module\'s onShutdown and leaves the others alone', async () => {
+  const file = path.join(tmpRoot, 'log.txt')
+  writeModule('aaa', { boot: '', shutdown: '', log: file })
+  writeModule('bbb', { boot: '', shutdown: '', log: file })
+  const loader = freshLoader(tmpRoot)
+  const model = fakeModel()
+
+  await lifecycle.boot({ modules: loader, model })
+  fs.writeFileSync(file, '')
+
+  const result = await lifecycle.stop('aaa', { modules: loader, model })
+
+  assert.deepEqual(result, { stopped: true, error: null })
+  // Only aaa. This is the difference from shutdown(), which runs everything.
+  assert.deepEqual(noted(file), ['shutdown:aaa'])
+  assert.equal(stateOf(loader, 'aaa').state, 'disabled')
+  assert.equal(stateOf(loader, 'bbb').state, 'started', 'the other module keeps running')
+  assert.equal(model.rows.get('aaa').state, 'disabled')
+})
+
+test('stop moves the record only after the hook has run', async () => {
+  // While onShutdown runs, the module is still `started` — the only state in
+  // which its routes and the world it is tearing down agree with each other. The
+  // module reports its own view of itself, so a record moved too early shows up
+  // here as `disabled` instead of `started`.
+  const file = path.join(tmpRoot, 'log.txt')
+  const dir = path.join(tmpRoot, 'aaa')
+  fs.mkdirSync(dir, { recursive: true })
+  fs.writeFileSync(path.join(dir, 'module.json'), JSON.stringify({
+    id: 'aaa', name: 'A', version: '1.0.0', coreApi: '^1.0.0', server: 'index.js',
+  }))
+  fs.writeFileSync(path.join(dir, 'index.js'), `
+    module.exports = (ctx, api) => {
+      api.onBoot(async () => {})
+      api.onShutdown(async () => {
+        const loader = require(${JSON.stringify(require.resolve('../src/modules/loader'))})
+        const me = loader.list().find((m) => m.id === 'aaa')
+        require('fs').appendFileSync(${JSON.stringify(file)}, 'state-during-hook:' + me.state + ${JSON.stringify('\n')})
+      })
+    }`)
+
+  const loader = freshLoader(tmpRoot)
+  await lifecycle.boot({ modules: loader, model: fakeModel() })
+  await lifecycle.stop('aaa', { modules: loader, model: fakeModel([{ id: 'aaa', state: 'started' }]) })
+
+  assert.deepEqual(noted(file), ['state-during-hook:started'])
+  assert.equal(stateOf(loader, 'aaa').state, 'disabled')
+})
+
+test('a hook that throws does not prevent the disable', async () => {
+  // The opposite of the boot path's rule, deliberately. There, a failure means
+  // the module never became safe to use; here, the operator has asked for it to
+  // stop answering and a module that could not close cleanly is a reason to log
+  // loudly, not a reason to leave it serving.
+  writeModule('aaa', { boot: '', shutdown: 'throw new Error("socket stuck")' })
+  const loader = freshLoader(tmpRoot)
+  const model = fakeModel()
+
+  await lifecycle.boot({ modules: loader, model })
+  const result = await lifecycle.stop('aaa', { modules: loader, model })
+
+  assert.equal(result.stopped, false)
+  assert.match(result.error, /socket stuck/)
+  assert.equal(stateOf(loader, 'aaa').state, 'disabled', 'disabled anyway')
+  assert.equal(model.rows.get('aaa').state, 'disabled')
+})
+
+test('a hook that hangs costs its budget, and the module is still disabled', async () => {
+  writeModule('aaa', { boot: '', shutdown: 'await new Promise(() => {})' })
+  const loader = freshLoader(tmpRoot)
+  const model = fakeModel()
+
+  await lifecycle.boot({ modules: loader, model })
+  const started = Date.now()
+  const result = await lifecycle.stop('aaa', { modules: loader, model, budgetMs: 50 })
+
+  assert.equal(result.stopped, false)
+  assert.match(result.error, /budget/)
+  assert.equal(stateOf(loader, 'aaa').state, 'disabled')
+  assert.ok(Date.now() - started < 2000)
+})
+
+test('stopping a module with no onShutdown still disables it', async () => {
+  // A hookless module has nothing to run and must still stop answering, or the
+  // guard and the row disagree about what is serving.
+  writeModule('aaa', { boot: '' })
+  const loader = freshLoader(tmpRoot)
+  const model = fakeModel()
+
+  await lifecycle.boot({ modules: loader, model })
+  const result = await lifecycle.stop('aaa', { modules: loader, model })
+
+  assert.deepEqual(result, { stopped: false, error: null })
+  assert.equal(stateOf(loader, 'aaa').state, 'disabled')
+  assert.equal(model.rows.get('aaa').state, 'disabled')
+})
+
+test('stopping a module whose onBoot failed does not run its onShutdown', async () => {
+  // Same rule shutdownHooks() applies: a module that never finished warming up
+  // has a half-built world its onShutdown was not written for. It is still
+  // disabled — it just is not asked to tear anything down.
+  const file = path.join(tmpRoot, 'log.txt')
+  writeModule('aaa', { boot: 'throw new Error("no")', shutdown: '', log: file })
+  const loader = freshLoader(tmpRoot)
+  const model = fakeModel()
+
+  await lifecycle.boot({ modules: loader, model })
+  const before = noted(file)
+  const result = await lifecycle.stop('aaa', { modules: loader, model })
+
+  assert.equal(result.stopped, false)
+  // Compared against what was already there rather than against an empty file:
+  // `noted` splits, so a blanked file reads as [''] and an emptiness assertion
+  // would pass for the wrong reason.
+  assert.deepEqual(noted(file), before, 'no new hook output')
+  assert.ok(!noted(file).includes('shutdown:aaa'))
+  assert.equal(stateOf(loader, 'aaa').state, 'disabled')
+})
+
+test('stopping an unknown id writes the row and does not throw', async () => {
+  // A row can exist for a module that is not on the volume, and disabling it is
+  // exactly what an operator would do about that.
+  writeModule('aaa', { boot: '' })
+  const loader = freshLoader(tmpRoot)
+  const model = fakeModel([{ id: 'ghost', state: 'startup_failed' }])
+
+  await assert.doesNotReject(() => lifecycle.stop('ghost', { modules: loader, model }))
+  assert.equal(model.rows.get('ghost').state, 'disabled')
+})
+
+test('a row that will not write does not stop the module from being disabled', async () => {
+  // The same rule the boot path follows: bookkeeping failure is not the
+  // operation failing. The guard is what stops traffic, and it has already moved.
+  writeModule('aaa', { boot: '', shutdown: '' })
+  const loader = freshLoader(tmpRoot)
+  const model = fakeModel()
+  await lifecycle.boot({ modules: loader, model })
+  model.disable = async () => { throw new Error('database is gone') }
+
+  await assert.doesNotReject(() => lifecycle.stop('aaa', { modules: loader, model }))
+  assert.equal(stateOf(loader, 'aaa').state, 'disabled')
+})