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/issues/activity_tracker.py

@@ -149,7 +149,7 @@ class IssueActivityTracker:
                     SELECT id FROM cost_periods
                     WHERE ? BETWEEN period_start AND period_end
                     ORDER BY created_at DESC LIMIT 1
-                ''', (activity_date,))
+                ''', (activity_date.isoformat(),))
                 result = cursor.fetchone()
                 if result:
                     period_id = result[0]
@@ -158,7 +158,7 @@ class IssueActivityTracker:
                 INSERT INTO issue_activity_log
                 (issue_id, activity_type, activity_date, period_id, activity_details)
                 VALUES (?, ?, ?, ?, ?)
-            ''', (issue_id, activity_type.value, activity_date, period_id, activity_details))
+            ''', (issue_id, activity_type.value, activity_date.isoformat(), period_id, activity_details))
 
             return cursor.lastrowid
 
@@ -294,11 +294,11 @@ class IssueActivityTracker:
 
             if start_date:
                 base_conditions.append('activity_date >= ?')
-                params.append(start_date)
+                params.append(start_date.isoformat() if hasattr(start_date, 'isoformat') else start_date)
 
             if end_date:
                 base_conditions.append('activity_date <= ?')
-                params.append(end_date)
+                params.append(end_date.isoformat() if hasattr(end_date, 'isoformat') else end_date)
 
             where_clause = ' AND '.join(base_conditions) if base_conditions else '1=1'
 
@@ -401,7 +401,7 @@ class IssueActivityTracker:
                         SELECT id FROM cost_periods
                         WHERE ? BETWEEN period_start AND period_end
                         ORDER BY created_at DESC LIMIT 1
-                    ''', (activity_date,))
+                    ''', (activity_date.isoformat() if hasattr(activity_date, 'isoformat') else activity_date,))
                     result = cursor.fetchone()
                     if result:
                         period_id = result[0]
@@ -410,7 +410,7 @@ class IssueActivityTracker:
                     INSERT INTO issue_activity_log
                     (issue_id, activity_type, activity_date, period_id, activity_details)
                     VALUES (?, ?, ?, ?, ?)
-                ''', (issue_id, activity_type.value, activity_date, period_id, activity_details))
+                ''', (issue_id, activity_type.value, activity_date.isoformat() if hasattr(activity_date, 'isoformat') else activity_date, period_id, activity_details))
 
                 activity_ids.append(cursor.lastrowid)