feat: Document-centric scan results + DSI deduplication

DSI Dedup (consent-tester):
- Only H1/H2 headings count as documents (not H3/H4 sub-sections)
- Sub-sections (Cookies, Betroffenenrechte, Social Media) are part of
  parent document's full text, not separate documents
- Reduces IHK result from 30 to ~11 real documents

Backend (agent_scan_routes):
- ScanFinding gets doc_title field linking each finding to its document
- doc_title set when creating DSI findings for document attribution

Frontend (ScanResult.tsx):
- 3 sections: Services table, Document cards, General findings
- Documents: expandable cards with completeness bar (green/yellow/red)
- Findings grouped under their parent document
- Each card shows: title, word count, findings count, % completeness
- Findings without doc_title go to "Allgemeine Findings" section

Email Summary (agent_scan_helpers):
- Findings listed under their parent document
- General findings in separate section
- No more flat mixed list

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend-compliance/compliance/api/agent_scan_routes.py

@@ -79,6 +79,7 @@ class ScanFinding(BaseModel):
     severity: str
     text: str
     correction: str = ""
+    doc_title: str = ""
     text_reference: TextReferenceModel | None = None
 
 
@@ -264,6 +265,7 @@ async def _execute_scan(req: ScanRequest, scan_id: str = "") -> ScanResponse:
                         if "SCORE" not in df.get("code", ""):
                             dsi_findings.append(ScanFinding(
                                 code=df["code"], severity=df["severity"], text=df["text"],
+                                doc_title=doc["title"],
                             ))
     except Exception as e:
         logger.warning("DSI discovery failed: %s %s", type(e).__name__, e)