fix: localize dashboard evidence, explain blocked vehicles, clarify pending odometers

Three content defects found by a live reviewer:

- Dashboard attention subtext was raw, untranslated evidence.summary text, and for
  11 of 15 seeded issues that text was literally "Synthetic deterministic seed
  issue". AttentionItem now exposes evidence_signals (stable code + params, same
  shape as the issue detail page) instead of a detail string; the frontend renders
  them through a shared describeEvidenceSignal() used by both the dashboard and the
  issue detail page. Every previously-placeholder seed row now cites a real,
  per-rule-type fact (a genuinely crossed service threshold, a genuinely blank
  field, or a real pair of booking odometer readings) instead of invented prose.

- 5 of 7 blocked vehicles had no quality issue at all and one had only a resolved
  one, so "needs attention" led nowhere. Each now has a real open
  missing_required_field issue backed by a genuinely blank field (no schema change,
  no migration -- reuses the existing data-quality pipeline).

- Booking odometer fields showing a bare "-" for 25 reserved + 1 active booking now
  show a localized explanation ("trip hasn't started yet" / "not yet closed").
  MO-024's rented-but-service-overdue contradiction was already caught by the
  vehicle-status evaluator (DQ-SCAN, vehicle.manual_review_required) -- added a
  regression test rather than new logic.

Also fixed a related bug the above exposed: the vehicle entity_snapshot omitted
registration_number entirely, so the "provide missing fields" form always showed
it blank regardless of the real value.

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

backend/app/api/routers/dashboard.py

@@ -19,6 +19,7 @@ from app.schemas import (
     AutomationRunOut,
     CurrentUser,
     DashboardOut,
+    EvidenceSignalOut,
     TodayItem,
 )
 from app.services.operations import compute_metrics
@@ -61,12 +62,21 @@ def get_dashboard(
             entity = customers_by_id.get(issue.entity_id)
             link_type = "customer"
         link_ref = entity.public_ref if entity else ""
+        # The backend never emits prose for the attention queue -- only stable signal
+        # codes + raw data params, exactly like the issue detail page's evidence list
+        # (see app/services/data_quality.py::_open_issue). The frontend is the one place
+        # that turns these into the operator's selected language; `evidence_json["summary"]`
+        # is a technical fallback only, never rendered here.
+        signals = [
+            EvidenceSignalOut(code=s["code"], params=s.get("params", {}))
+            for s in issue.evidence_json.get("signals", [])
+        ]
         attention_items.append(
             AttentionItem(
                 kind="quality_issue",
                 severity=issue.severity,
                 rule_type=issue.rule_type,
-                detail=issue.evidence_json.get("summary", ""),
+                evidence_signals=signals,
                 link_type=link_type,
                 link_ref=link_ref,
                 issue_ref=issue.public_ref,

backend/app/api/routers/data_quality.py

@@ -115,6 +115,7 @@ def _snapshot(entity_type: str, ref: str, db: Session) -> dict | None:
         return {
             "entity_type": "vehicle",
             "public_ref": vehicle.public_ref,
+            "registration_number": vehicle.registration_number,
             "make": vehicle.make,
             "model": vehicle.model,
             "location": vehicle.location,