Set human-readable titles for cron run sessions

[Interstellar-code]

Problem

Cron job runs are persisted as chat sessions with IDs like:

cron_<jobId>_<YYYYMMDD_HHMMSS>

However, those sessions do not get an explicit session title. The first persisted user message is the scheduler-injected cron guidance prefix:

[IMPORTANT: You are running as a scheduled cron job. DELIVERY: ...]

Downstream clients such as Hermes SwitchUI list sessions by title || preview, so cron-run sessions appear with the implementation warning ([IMPORTANT: ...]) instead of a useful name.

Current backend mechanism observed

In cron/scheduler.py:

• _build_job_prompt() prepends the cron execution/delivery hint to the user prompt.
• _run_job() creates a session id using cron_{job_id}_{timestamp}.
• The agent is constructed with platform="cron", session_id=_cron_session_id, and session_db=_session_db.
• No explicit title is assigned for that cron session.

Result: the session preview/title fallback is polluted by scheduler instructions.

Desired behavior

When the scheduler creates a cron-run session, it should set a deterministic title such as:

<cron job name> — <YYYY-MM-DD HH:mm>

Examples:

daily-brief — 2026-06-10 07:30
ProductHunt Daily Trends — 2026-06-09 15:09

This should happen server-side so every client benefits, not just SwitchUI.

Suggested implementation

After creating/opening the cron session DB row, set the title before or immediately after the run starts:

session_title = f"{job_name} — {_hermes_now().strftime('%Y-%m-%d %H:%M')}"
_session_db.set_session_title(_cron_session_id, session_title)

Consider a helper to sanitize/shorten with existing SessionDB.sanitize_title() rules and avoid uniqueness conflicts. If title uniqueness conflicts are possible for repeated/manual reruns within the same minute, include seconds or the short job id suffix.

Acceptance criteria

• Cron sessions no longer display [IMPORTANT: You are running as a scheduled cron job...] as their visible title.
• New cron run sessions have titles based on the cron job name and run timestamp.
• The original prompt/preview remains available for message history/search.
• Existing session deletion and lookup by cron_<jobId>_* remain compatible.
• Add/adjust tests covering cron session title creation.

Client-side workaround

SwitchUI can derive friendlier display names from the cron_<jobId>_<timestamp> session key and /api/claude-jobs, but this is only a compatibility workaround. The backend should own the canonical title.