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.

panel/src/lib/api/company-goals.ts

@@ -5,6 +5,7 @@ export interface CompanyGoals {
   objectives: Record<string, unknown>[];
   constraints: string[];
   operating_policy: Record<string, unknown>;
+  brand_voice: string;
   updated_at?: string | null;
   updated_by?: string | null;
 }
@@ -12,7 +13,11 @@ export interface CompanyGoals {
 export type CompanyGoalsUpdate = Partial<
   Pick<
     CompanyGoals,
-    "north_star" | "objectives" | "constraints" | "operating_policy"
+    | "north_star"
+    | "objectives"
+    | "constraints"
+    | "operating_policy"
+    | "brand_voice"
   >
 >;
 

panel/src/lib/api/x.ts

@@ -13,15 +13,21 @@ export interface XMentionRef {
   text: string;
 }
 
+export interface XFeatureRef {
+  slug: string;
+  title: string;
+}
+
 export interface XPost {
   task_id: string;
-  source: "x_post" | "x_reply";
+  source: "x_post" | "x_reply" | "x_feature";
   title: string;
   status: string;
   body: string;
   char_count: number;
   release_version?: string | null;
   mention?: XMentionRef | null;
+  feature?: XFeatureRef | null;
   reject_reason?: string | null;
 }