[TheGreatAxios]

Part of CL-12110: the invented fallbacks from the Findings document. Stacked on #167. The workspace split is the one CL-12096 will build on.

Changes

• pages/workspace/index.tsx is split. StageWorkspace keeps the project read, the room query and the coordinator start (which must run while the room loads), and shows the room fault or skeleton until the room is ready. ReadyRoom receives a loaded RoomSnapshot, so none of its hooks see undefined and the snapshot?.… ?? []/{} fallbacks are gone. A loading room no longer looks like an empty project.
• Agent activity stays undefined until it is read, and a failed read is toasted (wording in config.ts) instead of looking like nobody is working. Readers that depend on it skip their check while it is unknown.
• App.tsx and collaborators.tsx look up a refusal sentence only when the response has a code.
• An ask with no document no longer builds a sentence with an empty name; it uses its own wording.
• A dispatch call whose input is still streaming has no arguments rather than {}.
• LoadedDeliverable.versions is required, matching its only producer.

Verification

• New tests: an unread room shows the loading line, not the conversation, and a loaded snapshot renders the room; a failed activity read stays unknown while an empty read is an empty set.
• bun run lint, format:check, typecheck, test, pins:verify and vendor:verify pass.

[linear-code]

CL-12110

[corbits-triage]

Triage: Pass

No changes needed from you. A maintainer will review this pull request.

Stacked on #167: only this pull request's own changes were checked.

[corbits-triage]

No defects reported.