fix(pitch-deck): qwen3.5 thinking-mode deaktiviert, num_ctx 8192

Qwen3.5 denkt standardmaessig intern durch (think: true) — das
ueberschreitet den 2-Minuten-Timeout des Investor Agents.
think: false + num_ctx 8192 sorgt fuer schnelle direkte Antworten.

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

pitch-deck/app/api/chat/route.ts

@@ -180,9 +180,11 @@ export async function POST(request: NextRequest) {
         model: OLLAMA_MODEL,
         messages,
         stream: true,
+        think: false,
         options: {
           temperature: 0.4,
           num_predict: 4096,
+          num_ctx: 8192,
         },
       }),
       signal: AbortSignal.timeout(120000),