feat(techniques): status hover tooltips + min 2 tests for validated

1. Status logic (v3): require ≥2 validated tests with 'detected' result
   to reach 'validated' status. With only 1 validated+detected test the
   technique stays 'partial' (single test is insufficient evidence).
   Backfilled existing data: T1012 and T1059.001 downgraded to 'partial'.

2. Hover tooltips on status badges in TechniquesPage and TechniqueDetailPage:
   - validated: ≥2 tests executed and detected
   - partial: some tests done but incomplete coverage
   - in_progress: tests exist but none validated yet
   - not_covered: tests run but Blue Team didn't detect
   - not_evaluated: no tests created yet
   - review_required: recent update needs acknowledgment

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

backend/app/domain/entities/technique.py

@@ -115,17 +115,26 @@ class TechniqueEntity:
     ) -> TechniqueStatus:
         """Recompute ``status_global`` from a list of (state, detection_result) pairs.
 
-        Rules (v2):
+        Rules (v3):
           1. No tests -> not_evaluated
-          2. All validated -> inspect detection results:
-             - All detected -> validated
-             - Any partially_detected -> partial
-             - Otherwise -> not_covered
-          3. Some validated, others in progress -> partial
-          4. All in intermediate states -> in_progress
+          2. All tests validated -> inspect detection results:
+             a. All detected AND ≥ 2 validated tests -> validated
+             b. All detected but only 1 validated test -> partial
+                (single test is not enough evidence for full coverage)
+             c. Any partially_detected -> partial
+             d. Otherwise (no detected results) -> not_covered
+          3. Some validated, others in intermediate states -> partial
+          4. All tests in intermediate states (draft/executing/evaluating/review/rejected)
+             -> in_progress
+
+        Minimum validated count for "validated": 2 tests.
+        With only 1 validated+detected test the technique is "partial" to
+        signal that more testing is recommended.
 
         Returns the new status (also set on the entity).
         """
+        _MIN_VALIDATED_FOR_FULL = 2  # require ≥ N validated tests for "validated"
+
         tests = [
             _TestSnapshot(
                 state=s if isinstance(s, TestState) else TestState(s),
@@ -137,9 +146,14 @@ class TechniqueEntity:
         if not tests:
             self.status_global = TechniqueStatus.not_evaluated
         elif all(t.state == TestState.validated for t in tests):
+            validated_count = len(tests)
             results = [t.detection_result for t in tests if t.detection_result]
             if results and all(r == TestResult.detected or r == "detected" for r in results):
-                self.status_global = TechniqueStatus.validated
+                # Need at least _MIN_VALIDATED_FOR_FULL tests for "validated"
+                if validated_count >= _MIN_VALIDATED_FOR_FULL:
+                    self.status_global = TechniqueStatus.validated
+                else:
+                    self.status_global = TechniqueStatus.partial
             elif any(
                 r == TestResult.partially_detected or r == "partially_detected"
                 for r in results