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

scripts/trends/run-daily.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# RE-R3c headless entry: runs the DETERMINISTIC morning brief from a scheduler's
+# profile-less env (launchd/cron inherit no shell profile). No AI.
+#
+# The (e) slice will insert a pre-brief AI capture step here (poll -> score -> capture)
+# before the `brief` call below; R3c builds ONLY the deterministic store -> artifact path.
+#
+# Data-path: the FOURTH sanctioned twin of store.ts:defaultStorePath / data-root.mjs:getDataRoot
+# / analytics/src/utils/storage.ts:getDataRoot (the shell form of references/data-path-convention.md
+# rule 1). Keep in sync. Bash 3.2-compatible: ASCII-only, all expansions quoted, no bash-4 features.
+set -eu
+
+DIR="$(cd "$(dirname "$0")" && pwd)"
+cd "$DIR"                       # so `--import tsx` resolves node_modules even under cron's $HOME cwd
+
+NODE_BIN="${NODE_BIN:-$(command -v node 2>/dev/null || true)}"
+if [ -z "$NODE_BIN" ]; then
+  for c in /usr/local/bin/node /opt/homebrew/bin/node /usr/bin/node; do
+    if [ -x "$c" ]; then NODE_BIN="$c"; break; fi
+  done
+fi
+
+LOG="${LINKEDIN_STUDIO_DATA:-$HOME/.claude/linkedin-studio}/trends/cron.log"
+mkdir -p "$(dirname "$LOG")"
+TS="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+
+if [ -z "$NODE_BIN" ]; then
+  printf '%s exit=127 node not found\n' "$TS" >> "$LOG"
+  exit 127
+fi
+
+set +e
+OUT="$("$NODE_BIN" --import tsx "$DIR/src/cli.ts" brief "$@" --json 2>&1)"; CODE=$?
+set -e
+
+# `brief --json` is pretty-printed (cli.ts JSON.stringify(…, null, 2)); collapse it to ONE line.
+OUT="$(printf '%s' "$OUT" | tr '\n' ' ' | tr -s ' ')"
+printf '%s exit=%s %s\n' "$TS" "$CODE" "$OUT" >> "$LOG"
+exit "$CODE"