feat(web): projection-fed permission chip replaces the Access placeholder

PermissionSelect returns as the Access seat's wired occupant: options and
the current value read from the 'permissions' projection through the
standard-kit useProjection (no fetch, no mount timing — the resident
composer's mount-once fetch bug dies with the fetch), key absence renders
nothing (permission-less host, or a Draft with no session), and a pick
submits the '/permission <preset>' command line through the new
ComposerBarInjected.command callback (Session.command = command.execute
admission; the pushed projection frame lands the confirmed value). The
READONLY_OPTIONS placeholder and its local state leave InputBar.

The connection fixture mirrors the host: a permissions unit fold (three
knob events over the fixture preset table), the projections block +
baseline/push frames carry the key, and /permission joins the command
catalog with the same switch-through-knob-events handler shape.

packages/client/connection/tests/fixture-commands.spec.ts

@@ -23,7 +23,7 @@ describe('createFixtureApi commands/skills', () => {
     expect(response.rpcId).toBe(request.rpcId)
     if (!response.result.ok) throw new Error('list failed')
     const commands = response.result.value.commands
-    expect(commands.map(c => c.name)).toEqual(['compact', 'echo', 'goal-fixture'])
+    expect(commands.map(c => c.name)).toEqual(['compact', 'echo', 'goal-fixture', 'permission'])
     // input hint rides only the commands declaring it.
     const echo = commands.find(c => c.name === 'echo')
     expect(echo?.input?.hint).toBeTruthy()

packages/client/connection/tests/fixture.spec.ts

@@ -71,7 +71,17 @@ describe('createFixtureApi', () => {
     if (!empty.result.ok) throw new Error('empty failed')
     // Fixture composes the todos unit (host parallel when tool-todo is mounted): null before any write.
     expect(empty.result.value).toEqual({
-      events: [], hasMore: false, projections: { asOfSeq: -1, values: { todos: null } },
+      events: [], hasMore: false, projections: { asOfSeq: -1, values: {
+        todos: null,
+        // Permission unit composed: the composition-default select.
+        permissions: {
+          options: [
+            { value: 'workspace-write', name: 'workspace-write', description: 'Write inside the workspace and permitted temporary directories; wider retries require approval.' },
+            { value: 'danger-full-access', name: 'danger-full-access', description: 'Full file access without approval prompts.' },
+          ],
+          currentValue: 'workspace-write',
+        },
+      } },
     })
   })
 
@@ -206,7 +216,7 @@ describe('createFixtureApi', () => {
       const envelopes: RpcRequest<MuxFrame>[] = []
       for await (const envelope of api.events.mux(req({}), abort.signal)) {
         envelopes.push(envelope)
-        if (envelopes.length >= 4) abort.abort()
+        if (envelopes.length >= 5) abort.abort()
       }
       return envelopes
     }
@@ -214,13 +224,14 @@ describe('createFixtureApi', () => {
     const second = await openOnce()
     expect(first[0]?.payload).toMatchObject({ type: 'session/subscribed', sessionId: 'fx-alpha' })
     expect((first[0]?.payload as { lastSeq: number }).lastSeq).toBeGreaterThan(0)
-    // Projection baseline frames follow the subscribed frame (title + todos units).
+    // Projection baseline frames follow the subscribed frame (title + todos + permissions units).
     expect(first[1]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'title', value: 'Fixture 历史会话' })
     expect(first[2]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'todos' })
-    expect(first[3]?.payload).toMatchObject({ type: 'approval/requested', toolName: 'dangerous_tool' })
-    expect(second[3]?.rpcId).toBe(first[3]?.rpcId) // stable rpcId across replays (host replay semantics)
-    expect(first[4]?.payload).toMatchObject({ type: 'question/requested', sessionId: 'fx-alpha' })
-    expect(second[4]?.rpcId).toBe(first[4]?.rpcId)
+    expect(first[3]?.payload).toMatchObject({ type: 'session/projection', sessionId: 'fx-alpha', key: 'permissions' })
+    expect(first[4]?.payload).toMatchObject({ type: 'approval/requested', toolName: 'dangerous_tool' })
+    expect(second[4]?.rpcId).toBe(first[4]?.rpcId) // stable rpcId across replays (host replay semantics)
+    expect(first[5]?.payload).toMatchObject({ type: 'question/requested', sessionId: 'fx-alpha' })
+    expect(second[5]?.rpcId).toBe(first[5]?.rpcId)
   })
 
   it('steer with no replay in flight falls through to a fresh queued turn; non-text blocks stringify empty', async () => {