Bump version to 0.4.13

Technical Debt Implementation Release:
- Phase 0: Critical security fixes (authentication, error logging)
- Phase 1: Code quality (constants, type hints, deduplication)
- Phase 2: Performance (14 database indexes)
- Phase 3: Robustness (input validation, docstrings)

Statistics:
- 9/24 technical debt items complete (38%)
- 124 lines of code eliminated (44% reduction in container fetching)
- 1 critical security vulnerability fixed
- All 54 tests passing (100%)

Author: rsousa88

app/main.py

@@ -31,7 +31,7 @@
 load_dotenv()
 
 # Version
-VERSION = "0.4.12"
+VERSION = "0.4.13"
 
 HOST_METRICS_CACHE = {}
 HOST_METRICS_CACHE_TTL_SECONDS = 20