refactor(llm-deepseek)!: rename the provider route to deepseek-official

The native adapter's route was named deepseek, colliding with pi-ai's
catalog provider of the same name, so the two DeepSeek paths could never
be mounted side by side. The web settings page needs both configurable at
once. Compositions, fixtures, goldens, scaffolding defaults, and docs all
move together (pre-release, no shim); TUI/session-query-spill/
missing-credential goldens re-recorded through their keyless refresh
modes because provider-name length shifts box padding and spill
truncation points.

packages/client/connection/src/client/fixture.ts

@@ -556,7 +556,7 @@ export function createFixtureApi(options: FixtureOptions = {}): ApiProxy {
   const logs = new Map<SessionId, SessionEvent[]>([[sid('fx-alpha'), buildAlphaLog()]])
   const modelTargets = new Map<SessionId, ModelTarget>(sessions.map(session => [
     session.sessionId,
-    { provider: 'deepseek', model: 'deepseek-v4-flash' },
+    { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
   ]))
   const nextTurn = new Map<SessionId, number>([[sid('fx-alpha'), 60]])
   let nextSession = 1
@@ -839,7 +839,7 @@ export function createFixtureApi(options: FixtureOptions = {}): ApiProxy {
           sessionId: requestedId ?? sid(`fx-${nextSession++}`), updatedAt: Date.now(), running: false, blank: true, cwd,
         }
         sessions.push(created)
-        modelTargets.set(created.sessionId, { provider: 'deepseek', model: 'deepseek-v4-flash' })
+        modelTargets.set(created.sessionId, { provider: 'deepseek-official', model: 'deepseek-v4-flash' })
         attachedSessions += 1
         const emitSession = (): void => {
           // Mirrors the host: the frame fires at creation, so blank is constantly true.
@@ -878,10 +878,10 @@ export function createFixtureApi(options: FixtureOptions = {}): ApiProxy {
       },
       models: request => ok(request, {
         current: modelTargets.get(request.payload.sessionId)
-          ?? { provider: 'deepseek', model: 'deepseek-v4-flash' },
+          ?? { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
         groups: [
           {
-            id: 'deepseek',
+            id: 'deepseek-official',
             name: 'DeepSeek',
             models: [
               {

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

@@ -50,11 +50,11 @@ export class FakeApiClient implements IApiClient {
     () => Promise.resolve(ok({
       events: [],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'deepseek-chat' },
+      modelTarget: { provider: 'deepseek-official', model: 'deepseek-chat' },
     }))
 
   onModels: (payload: unknown) => Promise<RpcResponse<SessionModels>> = () => Promise.resolve(ok({
-    current: { provider: 'deepseek', model: 'deepseek-chat' },
+    current: { provider: 'deepseek-official', model: 'deepseek-chat' },
     groups: [],
     failures: [],
   }))