feat: add POST /api/cases/parties to store UYAP taraf bilgileri

The UYAP extension now captures the davaci/davali/sanik + vekil data
from the "Taraf Bilgileri" tab and sends it once per case. This
endpoint finds/creates the matching case by title (same lookup used
by registerLocalDocument, now shared via lib/caseLookup.ts) and stores
it in a new cases.parties column - a much more reliable source for
the case detail screen's "Taraflar" info than the AI's own guess from
OCR'd document text.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/controllers/document.controller.ts

@@ -3,6 +3,7 @@ import { supabase } from '../lib/supabase';
 import { AuthenticatedRequest } from '../middleware/auth';
 import * as officeParser from 'officeparser';
 import Tesseract from 'tesseract.js';
+import { findOrCreateCaseByTitle } from '../lib/caseLookup';
 const heicConvert = require('heic-convert');
 
 const ANALYSIS_SYSTEM_PROMPT = `
@@ -65,27 +66,7 @@ export const registerLocalDocument = async (req: AuthenticatedRequest, res: Resp
       return res.status(400).json({ error: 'case_title, filename ve extracted_text zorunludur.' });
     }
 
-    // Dava başlığına göre mevcut case'i bul (case-insensitive), yoksa oluştur.
-    const { data: existing } = await supabase
-      .from('cases')
-      .select('id, title')
-      .eq('user_id', userId)
-      .ilike('title', case_title)
-      .limit(1)
-      .maybeSingle();
-
-    let caseId: string;
-    if (existing) {
-      caseId = existing.id;
-    } else {
-      const { data: newCase, error: caseError } = await supabase
-        .from('cases')
-        .insert([{ title: String(case_title).slice(0, 200), user_id: userId }])
-        .select('id')
-        .single();
-      if (caseError) throw caseError;
-      caseId = newCase.id;
-    }
+    const caseId = await findOrCreateCaseByTitle(userId as string, case_title);
 
     const { data: documentRecord, error: docError } = await supabase
       .from('documents')