feat(linkedin-studio): RE-R3c — autonomous trigger (scheduler + headless entry) [skip-docs]

Closes research-engine hulls (1) no autonomous trigger + (6) no headless entry.
Makes the daily research loop closed + headless: deterministic-brief-only (C1),
print-first (C2 — the tool never runs launchctl or the cron table; --install writes
only the inert launchd plist file).

- NEW scripts/trends/src/schedule.ts — pure string emitters (launchd plist + cron-line +
  install/uninstall instructions + defaultLabel). No clock/fs/env/AI; byte-deterministic.
- NEW scripts/trends/run-daily.sh — bash-3.2 headless wrapper: resolves node, cd's into the
  package so tsx resolves, logs via the data-path twin seam; runs the deterministic brief and
  appends one compact cron.log line per fire. The (e) AI-capture seam is documented, not built.
- EDIT cli.ts — schedule --pillars <a,b> [--at HH:MM] [--fresh-days N]
  [--platform auto|launchd|cron] [--install|--uninstall] [--store <p>]; print-first, no new
  exit code; logPath anchored to dirname(defaultStorePath()) (not the --store override).
- WIRE trend-spotter.md (one prose line) + README (scheduler + wrapper + the C1 boundary).
- Gate: TRENDS_TESTS_FLOOR 171->192, ASSERT_BASELINE_FLOOR 105->111, new UNCONDITIONAL
  Section 16l (6 deps-absent greps + non-vacuity self-test), header-enum + floor-history append.

TDD two-phase RED -> GREEN. trends 192/192, gate 126/0, hook-suite 139/0 (untouched), plutil
-lint OK. No schema change (SCHEMA_VERSION 4 / BRIEF_SCHEMA_VERSION 1). Counts 29/19/27 unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011vmzxpsFpc8q19LaogAWLD

agents/trend-spotter.md

@@ -343,6 +343,11 @@ written to `<data-dir>/trends/morning-brief/YYYY-MM-DD.md` and ranks only on per
 (pillar overlap + `publishedAt`/`capturedAt` freshness, default 7-day window — tune with
 `--fresh-days N`). Skip silently if the store has no deps installed — same escape hatch as Step 4.5.
 
+The morning brief can also be **scheduled** to regenerate autonomously each morning — deterministic,
+from the current store — via `src/cli.ts schedule` (print-first: it emits a launchd/cron entry firing
+the `run-daily.sh` headless wrapper). That nightly run re-renders the brief only; your polling above
+stays the capture path (autonomous AI polling is a later slice).
+
 **Step 5: Compile digest**
 
 - Format using output template below