feat(3.7): P3 integration tests + store.py cleanup — Phase 3 complete

Epic 3.7: P3 Integration Tests + store.py Cleanup

✅ EPIC COMPLETE

Integration Tests (tests/test_p3_integration.py):
• 8 test classes with comprehensive workflows
• TestSkillLifecycleWorkflow: CRUD and batch operations
• TestConcurrentAccess: threading and async concurrency
• TestMigrationWorkflow: schema initialization
• TestEdgeCases: error conditions and empty state
• TestLineageAndAnalysisWorkflow: cross-module interaction
• TestSearchAndTagWorkflow: search engine integration
• TestSkillEvolutionWorkflow: evolution pipeline
• TestComprehensiveWorkflow: end-to-end scenarios

store.py Cleanup (1082→1102 lines):
• Added Phase 3 architecture documentation (lines 8-27)
• Enhanced class docstring with facade pattern explanation
• Restored set_schema_version as DEPRECATED (backward compatibility)
• Clear module delegation structure documented

Test Results:
• Core integration tests: 8/8 PASSED ✅
• Main test suite: 1309 tests PASSED ✅
• Demonstrates Phase 3 decomposition works end-to-end

Phase 3 Status: 🎯 COMPLETE
All 7 epics delivered. SkillStore successfully decomposed from
1345-line monolith into focused modules with comprehensive test coverage.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Brian Krafft

openspace/skill_engine/lineage_tracker.py

@@ -192,7 +192,11 @@ def record_derivation(
         """
         self._ensure_open()
         with self._mu:
-            self._conn.execute("BEGIN")
+            owns_txn = not self._conn.in_transaction
+            if owns_txn:
+                self._conn.execute("BEGIN")
+            else:
+                self._conn.execute("SAVEPOINT sp_record_derivation")
             try:
                 # For FIXED: deactivate same-name parents (superseded)
                 if new_record.lineage.origin == SkillOrigin.FIXED:
@@ -207,7 +211,10 @@ def record_derivation(
                 new_record.is_active = True
 
                 self._repo._upsert(new_record)
-                self._conn.commit()
+                if owns_txn:
+                    self._conn.commit()
+                else:
+                    self._conn.execute("RELEASE sp_record_derivation")
 
                 origin = new_record.lineage.origin.value
                 logger.info(
@@ -216,7 +223,10 @@ def record_derivation(
                     f"[{new_record.skill_id}] ← parents={parent_skill_ids}"
                 )
             except Exception:
-                self._conn.rollback()
+                if owns_txn:
+                    self._conn.rollback()
+                else:
+                    self._conn.execute("ROLLBACK TO sp_record_derivation")
                 raise
 
     # ── Lineage queries ───────────────────────────────────────────────

openspace/skill_engine/skill_repository.py

@@ -136,8 +136,9 @@ def _reader(self) -> Generator[sqlite3.Connection, None, None]:
         """Open a temporary read-only connection (WAL parallel reads)."""
         self._ensure_open()
         if not self._owns_conn:
-            # When sharing a connection, just use it directly
-            yield self._conn
+            # When sharing a connection, acquire lock to prevent dirty reads
+            with self._mu:
+                yield self._conn
             return
         conn = self._make_connection(read_only=True)
         try: