Merge remote-tracking branch 'origin/worktree/web-multimodal-image-input' into worktree/web-multimodal-image-input

# Conflicts:
#	.agents/notes/implemented/feature/2026-07-22-web-multimodal-image-input-and-durable-attachments.i18n.yaml
#	apps/web/tests/code-mode-fixture.snapshot.ts
#	apps/web/tests/image-display.snapshot.ts
#	docs/architecture.i18n.yaml
#	docs/module-graph.md
#	packages/client/test-runtime/tests/runtime.spec.tsx
#	packages/client/ui-conversation/src/client/skeleton/ConversationSession.tsx
#	packages/client/ui-conversation/tests/terminal-card.spec.tsx
#	packages/client/ui-trajectory/src/client/layout.ts

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

@@ -1,4 +1,4 @@
-import type { HostDescription, IApiClient, HostFrame, MuxFrame, RpcRequest } from './api.ts'
+import type { IApiClient, HostFrame, MuxFrame, RpcRequest } from './api.ts'
 
 /** Reconnect/backoff tunables (deployment-varying — no hardcoded tunables; web-cordis §B.1 lists
  *  these as the future `ctx.connection` plugin Config). All fields optional; defaults below. */
@@ -44,8 +44,6 @@ export type ConnectionState = 'connected' | 'reconnecting'
 export interface ConnectionSinks {
   onMuxEnvelope?: (envelope: RpcRequest<MuxFrame>) => void
   onHostEnvelope?: (envelope: RpcRequest<HostFrame>) => void
-  /** Latest successful host capability snapshot for this connection generation. */
-  onDescription?: (description: HostDescription) => void
   /** After each connection generation is established (both streams open + describe succeeded), first connect included. */
   onConnected?: () => void
   /** Coarse state transitions (deduplicated: fires only on change). The initial pre-connect
@@ -144,7 +142,6 @@ export class ConnectionController {
         }
         if (ac.signal.aborted) throw new Error('generation aborted during readiness handshake')
         this.attempt = 0
-        this.callSink(() => { this.sinks.onDescription?.(descriptionResult.value) })
         this.emitState('connected')
         this.callSink(this.sinks.onConnected)
       } catch {

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

@@ -1260,20 +1260,6 @@ export function createFixtureApi(options: FixtureOptions = {}): ApiProxy {
         cwd: '/tmp/fixture',
         provider: 'fixture',
         model: 'fx-vision',
-        activeModel: {
-          provider: 'fixture',
-          id: 'fx-vision',
-          name: 'Fixture Vision',
-          inputModalities: ['text', 'image'],
-          outputModalities: ['text', 'image'],
-        },
-        imageLimits: {
-          maxImageBytes: 5 * 1024 * 1024,
-          maxImagesPerMessage: 10,
-          maxMessageImageBytes: 20 * 1024 * 1024,
-          maxImagePixels: 40_000_000,
-          mediaTypes: ['image/png', 'image/jpeg', 'image/webp', 'image/gif'],
-        },
         attachedSessions,
       }),
       // Deterministic native pick: the keyless lanes drive the full