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>

app/modules/tenancy/models/merchant_domain.py

@@ -103,7 +103,7 @@ class MerchantDomain(Base, TimestampMixin):
         - EXAMPLE.COM -> example.com
         """
         # Remove protocol
-        domain = domain.replace("https://", "").replace("http://", "")  # SEC-034
+        domain = domain.replace("https://", "").replace("http://", "")  # noqa: SEC034
 
         # Remove trailing slash
         domain = domain.rstrip("/")

app/modules/tenancy/models/store_domain.py

@@ -92,7 +92,7 @@ class StoreDomain(Base, TimestampMixin):
         - EXAMPLE.COM -> example.com
         """
         # Remove protocol
-        domain = domain.replace("https://", "").replace("http://", "")  # SEC-034
+        domain = domain.replace("https://", "").replace("http://", "")  # noqa: SEC034
 
         # Remove trailing slash
         domain = domain.rstrip("/")