fix: eliminate all test suite warnings - Issue #129

Comprehensive fix for test suite warnings across multiple issue test files:

### SQLite3 Date Adapter Warnings (Python 3.12)
- Fixed 101 warnings in Issue 113 (activity_tracker.py)
- Fixed 55 warnings in Issue 114 (allocation_engine.py)
- Fixed 148 warnings in Issue 122 (worktime_tracker.py + test file)
- Fixed 18 warnings in Issue 124 (day_wrapup_commands.py + worktime_tracker.py)

### Pytest-asyncio Configuration
- Added asyncio_default_fixture_loop_scope = function to pytest.ini
- Eliminates pytest-asyncio deprecation warning

### Runtime Warnings for Unawaited Coroutines
- Fixed 2 warnings in Issue 59 (gitea plugin async mocking)
- Enhanced AsyncTestCase with better coroutine cleanup
- Improved async mock management in test utilities

### Technical Changes
- Convert Python date/datetime objects to ISO strings before SQLite queries
- Use .isoformat() with defensive hasattr() checks for backward compatibility
- Simplified async test mocking to avoid coroutine creation
- Enhanced cleanup_async_mocks() function for comprehensive cleanup

### Results
- Before: ~324 warnings across test suite
- After: 0 warnings - completely clean test suite
- All 216+ tests pass with zero warning noise

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

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

markitect/finance/allocation_engine.py

@@ -104,7 +104,7 @@ class TransactionManager:
                 (period_id, transaction_type, amount_eur, issue_id,
                  transaction_date, description)
                 VALUES (?, 'cost_allocated', ?, ?, ?, ?)
-            ''', (period_id, float(amount), issue_id, transaction_date, description))
+            ''', (period_id, float(amount), issue_id, transaction_date.isoformat() if hasattr(transaction_date, 'isoformat') else transaction_date, description))
 
             return cursor.lastrowid
 
@@ -136,7 +136,7 @@ class TransactionManager:
                 INSERT INTO cost_transactions
                 (period_id, transaction_type, amount_eur, transaction_date, description)
                 VALUES (?, 'loss_forward', ?, ?, ?)
-            ''', (to_period_id, float(amount), transaction_date, description))
+            ''', (to_period_id, float(amount), transaction_date.isoformat() if hasattr(transaction_date, 'isoformat') else transaction_date, description))
 
             return cursor.lastrowid
 
@@ -419,7 +419,7 @@ class AllocationEngine:
                         (period_id, transaction_type, amount_eur, issue_id,
                          transaction_date, description)
                         VALUES (?, 'adjustment', ?, ?, ?, ?)
-                    ''', (period_id, float(-amount), issue_id, date.today(), f"Reversal of allocation #{allocation_id}"))
+                    ''', (period_id, float(-amount), issue_id, date.today().isoformat(), f"Reversal of allocation #{allocation_id}"))
 
                     reversal_transaction_id = cursor2.lastrowid
 
@@ -527,7 +527,7 @@ class AllocationEngine:
                     INSERT INTO issue_cost_allocations
                     (issue_id, period_id, allocated_amount, allocation_date)
                     VALUES (?, ?, ?, ?)
-                ''', (issue_id, period_id, float(amount), allocation_date))
+                ''', (issue_id, period_id, float(amount), allocation_date.isoformat() if hasattr(allocation_date, 'isoformat') else allocation_date))
 
                 return cursor.lastrowid
         except sqlite3.IntegrityError: