Upstream advance: No project and name-only projects work with J5 features

[bryantderosier]

Part of #412. Milestone: Squadron fold. Depends on the ledger re-key (030). Lands with the next upstream advance past 67a2be0.

Outcome

Upstream's No project threads (pingdotgg#13612), name-only projects (pingdotgg#14527) and mobile's No project row (pingdotgg#14532) arrive as upstream built them, and J5 features work in them.

Decisions needed before merge (from #412)

1. Accept "No project" as the default container? This reverses the Squadron definition's "no junk drawer" decision, and should be recorded as a reversal.
2. One shared partition. All no-project threads on an environment share one ledger partition and one Fleet group. Under the same-project rule, agents in unrelated scratch threads can archive each other or merge back. Accept that, or add a J5 rule? (A J5 rule means fork cost.)
3. Peer Agents and Crews from a scratch thread. Do they share the parent's scratch folder or get their own? This depends on what spawn_agent passes (spawn_agent puts every Peer Agent in the caller's branch and worktree #274).

Scope

• Advance the pin. The new-thread seams the fold stack returned to upstream (DraftHeroHeadline, the palette's New thread in…, _chat.tsx shortcuts, the no-projects screen) should apply with no J5 conflict.
• Verify ledger, Exchanges, Crews and Fleet in a no-project thread and in a name-only project.
• Testing note: upstream hides No project when the home is inside a Git checkout, which a worktree's .j5code is. Use a home outside the checkout.

Done when

• A no-project thread can spawn a Peer Agent, exchange messages and appear in Fleet, on web and mobile.
• The three decisions are recorded in the register.