fix(agent): hide Anthropic-only assistant surfaces where the provider cannot run them (#2204) (#2343)

* fix(agent): hide Anthropic-only assistant surfaces where the provider cannot run them

Self-hosted deployments on an OpenAI-compatible provider (or with no AI
configured) still showed every entry point into the tool-loop runtime
behind /api/agent/invoke, which answers 503 there. The capability lived
server-side only (getAiStatus().assistantAvailable); no UI could read it.

Hand the flag to the client through CompanyContext (useAssistantAvailable,
beside the paid-capability gate) and gate each entry point that opens
AgentChat: the bookkeeping page's "Skapa med assistent" and "Med
assistenten", the inbox workspace's "Fråga assistenten" doors, /chat/intake
and /chat/new?intent=. The floating trigger falls back to general help (the
single-call console runs on any provider) instead of hiding, and AgentChat
itself never fires an invoke without the runtime, so a resumed thread or a
forgotten entry point shows a notice instead of a 503. The Hem checklist's
"Anslut till Claude" step renders only where the assistant runs on Claude
and the mcp-server extension is on. Provider-agnostic AI (ask console,
categorization, extraction) and the server-side 503 are unchanged; on
hosted the flag is true and nothing changes.

Closes #2204

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019SaJfqNi4VmsG8FMKq99G6

* test(ai): use a placeholder that cannot match an Anthropic key shape

The new direct-Anthropic status test assigned a string in the exact
format of a live API key, which trips secret scanners on every run. The
config only reads presence, so any non-empty string exercises the path.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

---------

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

lib/ai/__tests__/config.test.ts

@@ -199,6 +199,16 @@ describe('getAiStatus', () => {
     expect(s.models.extraction).toBe('eu.anthropic.claude-sonnet-5')
   })
 
+  it('is configured and assistant-capable on a direct Anthropic key', () => {
+    // Presence is all the config reads (no format check), so the placeholder
+    // deliberately cannot match a real key's shape and trip secret scanners.
+    process.env.ANTHROPIC_API_KEY = 'test-not-a-real-key'
+    const s = getAiStatus()
+    expect(s.provider).toBe('anthropic')
+    expect(s.configured).toBe(true)
+    expect(s.assistantAvailable).toBe(true)
+  })
+
   it('needs a model id on an OpenAI-compatible endpoint before it counts as configured', () => {
     byo('')
     const s = getAiStatus()