fix: Eliminate all 111 test warnings by fixing root causes

- Replace deprecated datetime.utcnow() with datetime.now(timezone.utc)
  across all domain models, services, infrastructure, and test files
- Add missing timezone imports to all affected files
- Fix pytest.ini configuration format from [tool:pytest] to [pytest]
- Remove warning suppressions to expose actual issues
- Ensure proper pytest marker registration for smoke tests

Results:
- 305 passed, 2 skipped, 0 warnings (down from 111 warnings)
- All functionality preserved with modern datetime API usage
- Improved code quality by addressing root causes vs suppression

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

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

tests/unit/domain/issues/test_issue_models.py

@@ -5,7 +5,7 @@ Tests pure business logic with no external dependencies.
 """
 
 import pytest
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 
 from domain.issues.models import Issue, Label, IssueState, LabelCategories
 from domain.issues.exceptions import IssueStateError
@@ -71,8 +71,8 @@ class TestIssue:
 
     def test_issue_creation_with_valid_data(self):
         # Arrange
-        created_at = datetime.utcnow()
-        updated_at = datetime.utcnow()
+        created_at = datetime.now(timezone.utc)
+        updated_at = datetime.now(timezone.utc)
         labels = [Label("bug"), Label("priority:high")]
 
         # Act
@@ -107,8 +107,8 @@ class TestIssue:
             title="Test",
             state=IssueState.OPEN,
             labels=labels,
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc)
         )
 
         # Act
@@ -128,8 +128,8 @@ class TestIssue:
             title="Test",
             state=IssueState.OPEN,
             labels=[],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc)
         )
 
         # Act
@@ -147,9 +147,9 @@ class TestIssue:
             title="Test",
             state=IssueState.CLOSED,
             labels=[],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow(),
-            closed_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+            closed_at=datetime.now(timezone.utc)
         )
 
         # Act & Assert
@@ -167,9 +167,9 @@ class TestIssue:
             title="Test",
             state=IssueState.CLOSED,
             labels=[],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow(),
-            closed_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+            closed_at=datetime.now(timezone.utc)
         )
 
         # Act
@@ -186,8 +186,8 @@ class TestIssue:
             title="Test",
             state=IssueState.OPEN,
             labels=[],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc)
         )
 
         # Act & Assert
@@ -203,8 +203,8 @@ class TestIssue:
             title="Test",
             state=IssueState.OPEN,
             labels=[Label("bug")],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc)
         )
         new_label = Label("priority:high")
 
@@ -223,8 +223,8 @@ class TestIssue:
             title="Test",
             state=IssueState.OPEN,
             labels=[label],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc)
         )
 
         # Act
@@ -240,8 +240,8 @@ class TestIssue:
             title="Test",
             state=IssueState.OPEN,
             labels=[Label("bug"), Label("priority:high")],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc)
         )
 
         # Act
@@ -258,8 +258,8 @@ class TestIssue:
             title="Test",
             state=IssueState.OPEN,
             labels=[Label("bug"), Label("priority:high")],
-            created_at=datetime.utcnow(),
-            updated_at=datetime.utcnow()
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc)
         )
 
         # Act & Assert