feat(cli): TUI resume has no discovery surface — no interrupted-session hint, and /resume errors when no session is attached

[me2seeks]

What happened

The TUI's safe-boundary resume has no discovery surface, so the feature is effectively invisible even when it would work:

1. No interrupted-session signal at startup. When the attached (or most recent) session has a failed/cancelled run that /resume could continue, the TUI shows nothing. The user must already know /resume exists and guess that it applies. Desktop solves this with an interrupted-turn banner carrying a Safe resume action (use-shell-resume.ts / AppShell); the TUI has no equivalent.
2. /resume with no session attached fails raw. In a fresh TUI (no session attached yet), /resume throws the driver's internal Cannot resume before a session starts. as a red error instead of helping the user reach a resumable session.

Reproduced live (with MAKA_RUNTIME_SAFE_BOUNDARY_RESUME=1):

• Provider turn fails with a 502 → exit → relaunch TUI in the same cwd → no indication anything is resumable; /resume only helps if you already switched back to that session via /session.
• Fresh TUI, no session attached → /resume → Error: Cannot resume before a session starts.

How to reproduce

1. MAKA_RUNTIME_SAFE_BOUNDARY_RESUME=1 maka in a project with an existing session
2. Send a message; have the turn fail (e.g. provider error) or cancel it with Esc
3. Relaunch the TUI in the same cwd — observe: no hint that the session has an interrupted run
4. In a TUI with no session attached, type /resume — observe the raw red error

Environment

• Maka version or commit: 944d822 (main, v0.1.11)
• OS and version: Linux x64
• Surface: TUI / CLI
• Node.js version, if running from source: 26.3.0

Expected behavior

• When the current/most-recent session for the cwd has an interrupted run (and the host reports resume available), the TUI shows an informational hint at startup/attach, e.g. "This session has an interrupted run — /resume to continue from the safe boundary." A passive hint is enough; no auto-resume is needed (Desktop owns the auto-resume policy).
• /resume with no session attached opens the session picker (scoped to resumable sessions where the driver reports them) instead of throwing Cannot resume before a session starts.

Logs, screenshots, or additional context

• Builds on fix(cli): TUI /resume can never succeed — safe-boundary resume disabled by unset env flag #3505 / PR fix(cli): surface parked /resume plans as informational notices, not errors #3506, which made parked plans render as informational notices; this issue is about the TUI never offering resume in the first place.
• Desktop already implements the discovery half of this story: interrupted-turn banner + Safe resume action + per-reason toast copy via resumeParkToastCopy in @maka/ui (note: that copy operates on runtime-level rejectionReasons and is currently zh-CN-only, while the TUI copy added in fix(cli): surface parked /resume plans as informational notices, not errors #3506 operates on protocol-level TurnResumeParkReason — sharing or aligning these two copy layers could be part of this work).
• Out of scope here: the Phase 3 production reconciler for indeterminate tool side effects (documented as designed-but-unwired in docs/architecture/runtime-resume-architecture.md) — that is a separate, larger runtime effort.

[me2seeks]

I'm working on this — as the follow-up to #3506, I'll add the startup interrupted-run hint and make /resume with no attached session open the session picker instead of erroring.