fix(prospecting): handle PageSpeed API errors and improve performance card

- Detect API-level errors (quota exceeded, invalid URL) in response JSON
  and store in scan_error instead of silently writing zeros
- Show scan error message on the performance card when present
- Show "No performance data — configure PAGESPEED_API_KEY" when all
  scores are 0 and no error was recorded
- Add accessibility and best practices scores to performance card

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

app/modules/prospecting/services/enrichment_service.py

@@ -210,6 +210,20 @@ class EnrichmentService:
             response = requests.get(api_url, params=params, timeout=60)
             data = response.json()
 
+            # Check for API-level errors (quota exceeded, invalid URL, etc.)
+            if "error" in data:
+                error_msg = data["error"].get("message", str(data["error"]))
+                logger.warning("PageSpeed API error for %s: %s", domain, error_msg)
+                profile = prospect.performance_profile
+                if not profile:
+                    profile = ProspectPerformanceProfile(prospect_id=prospect.id)
+                    db.add(profile)
+                profile.scan_error = error_msg
+                profile.scan_strategy = "mobile"
+                prospect.last_perf_scan_at = datetime.now(UTC)
+                db.flush()
+                return profile
+
             lighthouse = data.get("lighthouseResult", {})
             categories = lighthouse.get("categories", {})
             audits = lighthouse.get("audits", {})