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_cost_tasks.py

@@ -12,9 +12,8 @@ Note: These tests mock actual execution since they would require
 database access and Redis operations in production.
 """
 
-import pytest
-from unittest.mock import patch
 import uuid
+from unittest.mock import patch
 
 
 class TestAggregateDailyCostsTask:
@@ -22,8 +21,8 @@ class TestAggregateDailyCostsTask:
 
     def test_aggregate_daily_costs_task_exists(self):
         """Test that aggregate_daily_costs task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.cost  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.cost.aggregate_daily_costs" in celery_app.tasks
 
@@ -55,8 +54,8 @@ class TestCheckBudgetThresholdsTask:
 
     def test_check_budget_thresholds_task_exists(self):
         """Test that check_budget_thresholds task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.cost  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.cost.check_budget_thresholds" in celery_app.tasks
 
@@ -85,8 +84,8 @@ class TestRecordLlmUsageTask:
 
     def test_record_llm_usage_task_exists(self):
         """Test that record_llm_usage task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.cost  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.cost.record_llm_usage" in celery_app.tasks
 
@@ -159,8 +158,8 @@ class TestGenerateCostReportTask:
 
     def test_generate_cost_report_task_exists(self):
         """Test that generate_cost_report task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.cost  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.cost.generate_cost_report" in celery_app.tasks
 
@@ -211,8 +210,8 @@ class TestResetDailyBudgetCountersTask:
 
     def test_reset_daily_budget_counters_task_exists(self):
         """Test that reset_daily_budget_counters task is registered."""
-        from app.celery_app import celery_app
         import app.tasks.cost  # noqa: F401
+        from app.celery_app import celery_app
 
         assert "app.tasks.cost.reset_daily_budget_counters" in celery_app.tasks
 
@@ -363,7 +362,8 @@ class TestCostTaskSignatures:
     def test_cost_task_chain_creation(self):
         """Test that cost tasks can be chained together."""
         from celery import chain
-        from app.tasks.cost import record_llm_usage, check_budget_thresholds
+
+        from app.tasks.cost import check_budget_thresholds, record_llm_usage
 
         agent_id = str(uuid.uuid4())
         project_id = str(uuid.uuid4())