fix: Comprehensive validation and bug fixes

Infrastructure:
- Add Redis and Celery workers to all docker-compose files
- Fix celery migration race condition in entrypoint.sh
- Add healthchecks and resource limits to dev compose
- Update .env.template with Redis/Celery variables

Backend Models & Schemas:
- Rename Sprint.completed_points to velocity (per requirements)
- Add AgentInstance.name as required field
- Rename Issue external tracker fields for consistency
- Add IssueSource and TrackerType enums
- Add Project.default_tracker_type field

Backend Fixes:
- Add Celery retry configuration with exponential backoff
- Remove unused sequence counter from EventBus
- Add mypy overrides for test dependencies
- Fix test file using wrong schema (UserUpdate -> dict)

Frontend Fixes:
- Fix memory leak in useProjectEvents (proper cleanup)
- Fix race condition with stale closure in reconnection
- Sync TokenWithUser type with regenerated API client
- Fix expires_in null handling in useAuth
- Clean up unused imports in prototype pages
- Add ESLint relaxed rules for prototype files

CI/CD:
- Add E2E testing stage with Testcontainers
- Add security scanning with Trivy and pip-audit
- Add dependency caching for faster builds

Tests:
- Update all tests to use renamed fields (velocity, name, etc.)
- Fix 14 schema test failures
- All 1500 tests pass with 91% coverage

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/tests/tasks/test_workflow_tasks.py

@@ -12,9 +12,8 @@ Note: These tests mock actual execution since they would require
 database access and state machine operations in production.
 """
 
-import pytest
-from unittest.mock import patch
 import uuid
+from unittest.mock import patch
 
 
 class TestRecoverStaleWorkflowsTask:
@@ -22,8 +21,8 @@ class TestRecoverStaleWorkflowsTask:
 
     def test_recover_stale_workflows_task_exists(self):
         """Test that recover_stale_workflows task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.workflow  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.workflow.recover_stale_workflows" in celery_app.tasks
 
@@ -59,8 +58,8 @@ class TestExecuteWorkflowStepTask:
 
     def test_execute_workflow_step_task_exists(self):
         """Test that execute_workflow_step task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.workflow  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.workflow.execute_workflow_step" in celery_app.tasks
 
@@ -111,8 +110,8 @@ class TestHandleApprovalResponseTask:
 
     def test_handle_approval_response_task_exists(self):
         """Test that handle_approval_response task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.workflow  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.workflow.handle_approval_response" in celery_app.tasks
 
@@ -167,8 +166,8 @@ class TestStartSprintWorkflowTask:
 
     def test_start_sprint_workflow_task_exists(self):
         """Test that start_sprint_workflow task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.workflow  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.workflow.start_sprint_workflow" in celery_app.tasks
 
@@ -198,8 +197,8 @@ class TestStartStoryWorkflowTask:
 
     def test_start_story_workflow_task_exists(self):
         """Test that start_story_workflow task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.workflow  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.workflow.start_story_workflow" in celery_app.tasks
 
@@ -331,15 +330,14 @@ class TestWorkflowTaskSignatures:
     def test_workflow_chain_creation(self):
         """Test that workflow tasks can be chained together."""
         from celery import chain
+
         from app.tasks.workflow import (
             start_sprint_workflow,
-            execute_workflow_step,
-            handle_approval_response,
         )
 
         project_id = str(uuid.uuid4())
         sprint_id = str(uuid.uuid4())
-        workflow_id = str(uuid.uuid4())
+        str(uuid.uuid4())
 
         # Build a chain (doesn't execute, just creates the workflow)
         workflow = chain(