feat(pitch-deck): add force recompute to bypass stale pitch_fm_results cache

Adds `force: true` body param to POST /api/financial-model/compute that
skips the cached results check and recomputes from assumptions directly.
Exposes this via a "Force Recompute" button on the scenario edit admin page,
so updating assumptions directly in the DB can be followed by a cache bust
without touching the UI assumption flow.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

pitch-deck/app/api/financial-model/compute/route.ts

@@ -6,7 +6,7 @@ import { finanzplanToFMResults } from '@/lib/finanzplan/adapter'
 export async function POST(request: NextRequest) {
   try {
     const body = await request.json()
-    const { scenarioId, source } = body
+    const { scenarioId, source, force } = body
 
     // If source=finanzplan, use the Finanzplan engine instead
     if (source === 'finanzplan') {
@@ -28,8 +28,8 @@ export async function POST(request: NextRequest) {
 
     const client = await pool.connect()
     try {
-      // Fast path: return cached results if they exist (avoid expensive recompute + 60 inserts)
-      const cached = await client.query(
+      // Fast path: return cached results if they exist (skip when force=true)
+      const cached = force ? { rows: [] } : await client.query(
         'SELECT * FROM pitch_fm_results WHERE scenario_id = $1 ORDER BY month',
         [scenarioId]
       )