test: improve test coverage from 61% to 84.81%

Major improvements:
- Fixed all 42 broken tests (database connection leaks)
- Added db_connection() context manager for proper cleanup
- Created comprehensive test suites for undertested modules

New test coverage:
- tools/general_tools.py: 26 tests (97% coverage)
- tools/price_tools.py: 11 tests (validates NASDAQ symbols, date handling)
- api/price_data_manager.py: 12 tests (85% coverage)
- api/routes/results_v2.py: 3 tests (98% coverage)
- agent/reasoning_summarizer.py: 2 tests (87% coverage)
- api/routes/period_metrics.py: 2 edge case tests (100% coverage)
- agent/mock_provider: 1 test (100% coverage)

Database fixes:
- Added db_connection() context manager to prevent leaks
- Updated 16+ test files to use context managers
- Fixed drop_all_tables() to match new schema
- Added CHECK constraint for action_type
- Added ON DELETE CASCADE to trading_days foreign key

Test improvements:
- Updated SQL INSERT statements with all required fields
- Fixed date parameter handling in API integration tests
- Added edge case tests for validation functions
- Fixed import errors across test suite

Results:
- Total coverage: 84.81% (was 61%)
- Tests passing: 406 (was 364 with 42 failures)
- Total lines covered: 6364 of 7504

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

tests/unit/test_database_helpers.py

@@ -31,8 +31,8 @@ class TestDatabaseHelpers:
         """Test creating a new trading day record."""
         # Insert job first
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         trading_day_id = db.create_trading_day(
@@ -61,8 +61,8 @@ class TestDatabaseHelpers:
         """Test retrieving previous trading day."""
         # Setup: Create job and two trading days
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         day1_id = db.create_trading_day(
@@ -103,8 +103,8 @@ class TestDatabaseHelpers:
     def test_get_previous_trading_day_with_weekend_gap(self, db):
         """Test retrieving previous trading day across weekend."""
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         # Friday
@@ -171,8 +171,8 @@ class TestDatabaseHelpers:
     def test_get_ending_holdings(self, db):
         """Test retrieving ending holdings for a trading day."""
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         trading_day_id = db.create_trading_day(
@@ -201,8 +201,8 @@ class TestDatabaseHelpers:
     def test_get_starting_holdings_first_day(self, db):
         """Test starting holdings for first trading day (should be empty)."""
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         trading_day_id = db.create_trading_day(
@@ -224,8 +224,8 @@ class TestDatabaseHelpers:
     def test_get_starting_holdings_from_previous_day(self, db):
         """Test starting holdings derived from previous day's ending."""
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         # Day 1
@@ -318,8 +318,8 @@ class TestDatabaseHelpers:
     def test_create_action(self, db):
         """Test creating an action record."""
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         trading_day_id = db.create_trading_day(
@@ -355,8 +355,8 @@ class TestDatabaseHelpers:
     def test_get_actions(self, db):
         """Test retrieving all actions for a trading day."""
         db.connection.execute(
-            "INSERT INTO jobs (job_id, status) VALUES (?, ?)",
-            ("test-job", "running")
+            "INSERT INTO jobs (job_id, config_path, status, date_range, models, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            ("test-job", "configs/test.json", "running", '["2025-01-15"]', '["test-model"]', "2025-01-15T00:00:00Z")
         )
 
         trading_day_id = db.create_trading_day(