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>

pyproject.toml

@@ -74,6 +74,9 @@ ignore = [
     "UP042",   # str+Enum → StrEnum — requires Python 3.11+ migration, do incrementally
 ]
 
+# External linter codes used in # noqa comments (architecture/security/performance validators)
+external = ["SEC", "PERF", "MOD", "EXC"]
+
 # Allow autofix for all rules
 fixable = ["ALL"]
 unfixable = []