feat(marketing): HoM feature-spotlight X drafts + brand-voice charter (v0.18.0 B)

The Head of Marketing now markets features, not just releases: a default-off
x_feature_spotlight loop periodically spawns the HoM to investigate what shipped
(CHANGELOG, feature flags, docs/map, KB) and draft ONE held marketing post via
propose_feature_spotlight, reviewed in the X post queue.

- New x_feature source (distinct from x_post, fixing panel mislabeling) + a
  panel Feature-spotlight branch.
- brand_voice column on company_goals (migration 061, single head) as the
  CEO-editable voice source, surfaced in Settings and injected into the HoM
  briefing; a VOICE GUIDE baseline in head-marketing.md.
- propose_feature_spotlight verb (HoM-only), mirroring propose_roadmap.

Gated by x_feature_spotlight_enabled (default off; flag-off dormancy proven).
Also fixed two real bugs found mid-build: company_goals API schemas dropped
brand_voice on GET/PUT; the live charter UI is goals-tab.tsx, not the unmounted
company-goals-card.tsx. Full suite green (2935); migration single-head verified.

tests/unit/runtime/test_feature_spotlight_loop_dormant.py

@@ -0,0 +1,60 @@
+"""The feature-spotlight orchestrator loop is fully dormant unless BOTH the X
+engine and the feature-spotlight sub-switch are enabled (both default off).
+
+With either flag off, ``_x_feature_spotlight_loop`` must return immediately —
+no sleep, no HTTP, no DB, no Head-of-Marketing spawn — so a standard
+deployment (or one running only release posts / mention replies) behaves
+exactly as today.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import types
+from typing import cast
+
+import pytest
+from roboco.config import settings as cfg
+from roboco.runtime.orchestrator import AgentOrchestrator
+
+
+@pytest.mark.asyncio
+async def test_x_feature_spotlight_loop_returns_immediately_when_disabled(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(cfg, "x_engine_enabled", False)
+    monkeypatch.setattr(cfg, "x_feature_spotlight_enabled", False)
+    stub = cast("AgentOrchestrator", types.SimpleNamespace(_running=True))
+    # Gated off -> returns at once. If the gate were missing it would sleep the
+    # full interval and this wait_for would time out.
+    await asyncio.wait_for(
+        AgentOrchestrator._x_feature_spotlight_loop(stub), timeout=1.0
+    )
+
+
+@pytest.mark.asyncio
+async def test_x_feature_spotlight_loop_dormant_when_only_subswitch_disabled(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """x_engine_enabled on but the feature-spotlight sub-switch off: still
+    dormant — the engine still runs release posts/mention replies via their
+    own loops, unaffected."""
+    monkeypatch.setattr(cfg, "x_engine_enabled", True)
+    monkeypatch.setattr(cfg, "x_feature_spotlight_enabled", False)
+    stub = cast("AgentOrchestrator", types.SimpleNamespace(_running=True))
+    await asyncio.wait_for(
+        AgentOrchestrator._x_feature_spotlight_loop(stub), timeout=1.0
+    )
+
+
+@pytest.mark.asyncio
+async def test_x_feature_spotlight_loop_dormant_when_only_engine_disabled(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """The subswitch alone is not enough — x_engine_enabled must also be on."""
+    monkeypatch.setattr(cfg, "x_engine_enabled", False)
+    monkeypatch.setattr(cfg, "x_feature_spotlight_enabled", True)
+    stub = cast("AgentOrchestrator", types.SimpleNamespace(_running=True))
+    await asyncio.wait_for(
+        AgentOrchestrator._x_feature_spotlight_loop(stub), timeout=1.0
+    )