fix: actionable diagnostics for empty feed/inbox results

[cosmicallycooked]

Bug

When sonar feed or sonar inbox returns zero results, the CLI outputs a single dim line:

No tweets found in this window.

Inbox is empty.

Neither message explains why the result is empty or what the operator should do next. Common root causes include: no interests configured, ingest hasn't run, time window too narrow, all inbox items already actioned, or an auth/quota issue — none of which are surfaced.

For agents consuming --json output the situation is worse: an empty array [] on stdout is indistinguishable from a genuinely quiet period versus a broken data pipeline.

Fix

Terminal (non-JSON) path

sonar feed — context-aware numbered checklist tailored to --kind:

• bookmarks kind → directs to sonar ingest bookmarks + monitor
• All other kinds → widen window, check interests, trigger ingest, run matching, check account

sonar inbox — adapts to the active --status filter:

• If a specific status is set, first step is sonar inbox --all (maybe items exist under a different status)
• Then: verify interests, ingest, match, monitor, check account

Both render with a yellow header so empty is visually distinct from a normal (populated) result.

JSON path

When result is empty in --json mode, a structured diagnostic is written to stderr (stdout still receives the valid empty JSON array []). This means:

• Piped agents get a machine-readable empty array and can proceed
• Humans reading stderr (or agents that check it) see labelled causes and remediation commands
• Exit code is still 0 — empty is not an error

Example output (terminal)

sonar feed --hours 1

No tweets found.
No network tweets matched your interests in the last 1h.
Things to check:
  1. Widen the window:         sonar feed --hours 48 or --days 7
  2. Check interests exist:    sonar interests
  3. Trigger ingest if stale:  sonar ingest tweets
  4. Check ingest progress:    sonar ingest monitor
  5. Run matching:             sonar interests match
Account status and quota: sonar account

Example output (JSON stderr)

sonar feed --json 2>&1 1>/dev/null
[sonar feed] Empty result — possible causes:
  • No tweets matched your interests in the last 12h.
  • Check interests are configured: sonar interests
  • Ingest may be stale: sonar ingest tweets && sonar ingest monitor
  • Widen the window: sonar feed --hours 48
  • Account/quota status: sonar account

[cosmicallycooked]

@1a35e1 PR is approved and ready to merge.