feat(validators): add noqa suppression support to security and performance validators

- Add centralized _is_noqa_suppressed() to BaseValidator with normalization
  (accepts both SEC001 and SEC-001 formats for ruff compatibility)
- Wire noqa support into all 21 security and 18 performance check functions
- Add ruff external config for SEC/PERF/MOD/EXC codes in pyproject.toml
- Convert all 280 Python noqa comments to dashless format (ruff-compatible)
- Add site/ to IGNORE_PATTERNS (excludes mkdocs build output)
- Suppress 152 false positive findings (test passwords, seed data, validator
  self-references, Apple Wallet SHA1, etc.)
- Security: 79 errors → 0, 60 warnings → 0
- Performance: 80 warnings → 77 (3 test script suppressions)
- Add proposal doc with noqa inventory and remaining findings recommendations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

conftest.py

@@ -128,7 +128,7 @@ def db(engine, testing_session_local):
             # Disable FK checks temporarily for fast truncation
             conn.execute(text("SET session_replication_role = 'replica'"))
             for table in reversed(Base.metadata.sorted_tables):
-                conn.execute(text(f'TRUNCATE TABLE "{table.name}" CASCADE'))  # noqa: SEC-011
+                conn.execute(text(f'TRUNCATE TABLE "{table.name}" CASCADE'))  # noqa: SEC011
             conn.execute(text("SET session_replication_role = 'origin'"))
             conn.commit()