docs(planning): record v1.4.20.1 hotfix wave

New `.planning/phase-v1421-hotfix-report.md` summarises the six
fixes (Daily Briefing regenerate · Coach day-level snapshot · Coach
prompt update · streaming-bubble dedup · drawer header · sources rail
scope picker), the test-count delta (2026 → 2036 unit), the
token-budget impact of the day-level snapshot (~190 → ~3000 tokens
per full-scope turn), and a recommendation to ship as a v1.4.20.1
hotfix.

STATE.md grows a Phase F section + status block tracking the six
commits on develop. Includes prettier polish across the touched
coach surfaces (sources-rail, drawer, message-thread, snapshot,
chat route).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/api/insights/chat/route.ts

@@ -143,12 +143,7 @@ async function handleChatRequest(request: NextRequest): Promise<Response> {
       { status: 422 },
     );
   }
-  const {
-    conversationId,
-    message,
-    locale: bodyLocale,
-    scope,
-  } = parsed.data;
+  const { conversationId, message, locale: bodyLocale, scope } = parsed.data;
 
   await enforceBudget(userId);