refactor(commands): move the command service to Remote

`CommandService.list` and `execute` carry the wire contract directly through
`@Remote`, and the Client assembly mounts the generated commands
contribution. The legacy API Proxy route, its schemas, the map rows, the
generated client methods and the fixture's command domain are removed, so the
catalog and the admission call have one owner again.

`Session.command()` keeps a result-shaped public face for parity with the
prompt, cancel and attachment neighbours it sits beside, and reads the
generated namespace through one `SessionRemotes` parameter. The Session
cluster declares that face against the owning business package rather than the
generated contribution: the Host compiler aggregate builds this package, and
it runs before any contribution is emitted.

Migrated calls lose the `title-invalid` class of protocol-only error codes and
report `internal`; no production caller branched on them.

packages/client/connection/tests/fake-api.ts

@@ -1,9 +1,8 @@
 // Test-local programmable IApiClient fake (NOT the fixture: fixture is a demo
 // data source on a real clock; behavior tests need per-case responses and
 // deferred-controlled timing). Streams are hand pumps: pushMux/pushHost.
-import type { CommandId } from '@deepseek-ai/dsh-commands/brand'
 import type {
-  CommandDescriptor, HostFrame, IApiClient, ModelSelection, MuxFrame,
+  HostFrame, IApiClient, ModelSelection, MuxFrame,
   RpcRequest, RpcResponse, SessionId, SessionModels, SessionSearchItem, SkillEntry,
 } from '../src/client/api.ts'
 import { RpcId } from '../src/client/api.ts'
@@ -169,19 +168,10 @@ export class FakeApiClient implements IApiClient {
 
   // Payloads stay `unknown` (lint-lane note above); response rows are the real
   // wire shapes so cases can program catalogs and skill lists without casts.
-  onCommandList: (payload: unknown) => Promise<RpcResponse<{ commands: CommandDescriptor[] }>>
-    = () => Promise.resolve(ok({ commands: [] }))
-  onCommandExecute: (payload: unknown) => Promise<RpcResponse<{ matched: boolean; commandId?: CommandId }>>
-    = () => Promise.resolve(ok({ matched: false }))
   onSkillList: (payload: unknown) => Promise<RpcResponse<{ skills: SkillEntry[] }>>
     = () => Promise.resolve(ok({ skills: [] }))
 
 
-  readonly commands: IApiClient['commands'] = {
-    list: (payload: unknown) => this.record('command.list', payload, this.onCommandList(payload)),
-    execute: (payload: unknown) => this.record('command.execute', payload, this.onCommandExecute(payload)),
-  }
-
   readonly agentPresets: IApiClient['agentPresets'] = {
     list: (payload: unknown) => this.record('agentPreset.list', payload, Promise.resolve(ok({ presets: [], authorable: false, hasDocument: false }))),
     select: (payload: { agentPreset: string }) =>

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

@@ -1,28 +1,35 @@
 /**
- * Fixture commands/skills domains: contract-shape conformance for the two
- * domains added to ApiProxy — rpcId echo, session-addressed catalogs, execute
- * parse/dispatch, skill.list session resolution, and the FixtureApiClient
- * dispatch rows.
+ * Fixture commands/skills domains: session-addressed catalogs, execute
+ * parse/dispatch and its logged lifecycle pair, skill.list session resolution,
+ * and the FixtureApiClient dispatch rows. Commands answer on the Remote face
+ * and skills on the legacy API face, so both are driven here.
  */
 import { describe, expect, it } from 'vitest'
 import type { SessionId } from '../src/client/api.ts'
 import { RpcId } from '../src/client/api.ts'
 import type { RpcRequest } from '../src/client/api.ts'
-import { FixtureApiClient, createFixtureApi } from '../src/client/fixture.ts'
+import { FixtureApiClient, createFixtureApi, createFixtureFaces } from '../src/client/fixture.ts'
+
+/** Drive one commands Remote endpoint against the fixture state graph. */
+async function callRemote<T>(
+  rpc: ReturnType<typeof createFixtureFaces>['rpc'],
+  endpoint: string,
+  args: Record<string, unknown>,
+): Promise<T> {
+  const result = await rpc.call('/api', endpoint, { args })
+  if (!result.ok) throw new Error(`${endpoint} failed: ${result.error.code}`)
+  return result.value as T
+}
 
 const sid = (id: string): SessionId => id as SessionId
 let reqCount = 0
 const req = <P>(payload: P): RpcRequest<P> => ({ rpcId: RpcId(`t-${reqCount++}`), payload })
-const signal = new AbortController().signal
 
 describe('createFixtureApi commands/skills', () => {
-  it('serves the addressed session catalog with rpcId echo', async () => {
-    const api = createFixtureApi()
-    const request = req({ sessionId: sid('fx-alpha') })
-    const response = await api.commands.list(request)
-    expect(response.rpcId).toBe(request.rpcId)
-    if (!response.result.ok) throw new Error('list failed')
-    const commands = response.result.value.commands
+  it('serves the addressed session catalog', async () => {
+    const { rpc } = createFixtureFaces()
+    const commands = await callRemote<{ name: string; input?: { hint: string } }[]>(
+      rpc, 'commands/list', { agentId: sid('fx-alpha') })
     expect(commands.map(c => c.name)).toEqual(['compact', 'echo', 'goal', 'permission', 'plan'])
     // input hint rides only the commands declaring it.
     const echo = commands.find(c => c.name === 'echo')
@@ -31,13 +38,13 @@ describe('createFixtureApi commands/skills', () => {
   })
 
   it('rejects a catalog request for an unknown session', async () => {
-    const api = createFixtureApi()
-    const response = await api.commands.list(req({ sessionId: sid('fx-nope') }))
-    expect(response.result).toMatchObject({ ok: false, error: { code: 'session-not-found' } })
+    const { rpc } = createFixtureFaces()
+    const result = await rpc.call('/api', 'commands/list', { args: { agentId: sid('fx-nope') } })
+    expect(result).toMatchObject({ ok: false, error: { code: 'session-not-found' } })
   })
 
   it('executes a known command line: pure admission plus a mux-broadcast lifecycle pair', async () => {
-    const api = createFixtureApi()
+    const { api, rpc } = createFixtureFaces()
     const frames: unknown[] = []
     const abort = new AbortController()
     const stream = api.events.mux(req({}), abort.signal)
@@ -47,10 +54,9 @@ describe('createFixtureApi commands/skills', () => {
         if (frames.filter(f => (f as { type: string }).type === 'session/event').length >= 2) abort.abort()
       }
     })()
-    const response = await api.commands.execute(req({ sessionId: sid('fx-alpha'), line: '/echo hello world' }), signal)
-    if (!response.result.ok) throw new Error('execute failed')
-    expect(response.result.value).toMatchObject({ matched: true })
-    expect(response.result.value.commandId).toBeTruthy()
+    const execution = await callRemote<{ commandId: string } | undefined>(
+      rpc, 'commands/execute', { agentId: sid('fx-alpha'), line: '/echo hello world' })
+    expect(execution?.commandId).toBeTruthy()
     await pump
     const events = frames
       .filter((f): f is { type: string; event: { type: string; data: Record<string, unknown> } } => (f as { type: string }).type === 'session/event')
@@ -63,22 +69,23 @@ describe('createFixtureApi commands/skills', () => {
   })
 
   it('addresses execute to the session; an unknown session errs', async () => {
-    const api = createFixtureApi()
-    const hit = await api.commands.execute(req({ sessionId: sid('fx-alpha'), line: '/goal ship' }), signal)
-    if (!hit.result.ok) throw new Error('execute failed')
-    expect(hit.result.value.matched).toBe(true)
+    const { rpc } = createFixtureFaces()
+    const hit = await callRemote<{ commandId: string } | undefined>(
+      rpc, 'commands/execute', { agentId: sid('fx-alpha'), line: '/goal ship' })
+    expect(hit?.commandId).toBeTruthy()
 
-    const missing = await api.commands.execute(req({ sessionId: sid('fx-nope'), line: '/goal ship' }), signal)
-    expect(missing.result).toMatchObject({ ok: false, error: { code: 'session-not-found' } })
+    const missing = await rpc.call('/api', 'commands/execute', {
+      args: { agentId: sid('fx-nope'), line: '/goal ship' },
+    })
+    expect(missing).toMatchObject({ ok: false, error: { code: 'session-not-found' } })
   })
 
-  it('falls to matched:false on unknown names and non-command lines', async () => {
-    const api = createFixtureApi()
+  it('answers no execution for unknown names and non-command lines', async () => {
+    const { rpc } = createFixtureFaces()
     for (const line of ['/nope', 'plain text', '/']) {
-      const response = await api.commands.execute(req({ sessionId: sid('fx-alpha'), line }), signal)
-      if (!response.result.ok) throw new Error('execute failed')
-      // Pure admission value: the matched bit is the whole response shape.
-      expect(response.result.value).toEqual({ matched: false })
+      // Absence is the whole answer: nothing matched, so no lifecycle id exists.
+      expect(await callRemote(rpc, 'commands/execute', { agentId: sid('fx-alpha'), line }))
+        .toBeUndefined()
     }
   })
 
@@ -94,14 +101,13 @@ describe('createFixtureApi commands/skills', () => {
 })
 
 describe('FixtureApiClient command/skill dispatch', () => {
-  it('routes the three method keys through the in-memory dispatch table', async () => {
+  it('routes the Remote commands face and the legacy skill row through one state graph', async () => {
     const client = new FixtureApiClient()
-    const list = await client.commands.list({ sessionId: sid('fx-alpha') })
-    if (!list.result.ok) throw new Error('command.list failed')
-    expect(list.result.value.commands.length).toBeGreaterThan(0)
-    const executed = await client.commands.execute({ sessionId: sid('fx-alpha'), line: '/compact' })
-    if (!executed.result.ok) throw new Error('command.execute failed')
-    expect(executed.result.value.matched).toBe(true)
+    const commands = await callRemote<{ name: string }[]>(client.rpc, 'commands/list', { agentId: sid('fx-alpha') })
+    expect(commands.length).toBeGreaterThan(0)
+    const executed = await callRemote<{ commandId: string } | undefined>(
+      client.rpc, 'commands/execute', { agentId: sid('fx-alpha'), line: '/compact' })
+    expect(executed?.commandId).toBeTruthy()
     const skills = await client.skills.list({ sessionId: sid('fx-alpha') })
     if (!skills.result.ok) throw new Error('skill.list failed')
     expect(skills.result.value.skills.length).toBeGreaterThan(0)