feat: harden generic preset, add LLM retry, and finish tooling/docs

- PatternDef.validate + Luhn-gated credit-card detection; de-overlap the
  generic phone/date/IP patterns; presets.swiss unchanged (production behavior)
- strip g/y flags from nameHint so .test() is stateless (latent footgun)
- openAICompatibleProvider: bounded retry on transient failures (network /
  timeout / 429 / 5xx), configurable via retries + retryDelayMs
- eslint + prettier + vitest coverage (97%); CI runs lint/format/coverage
- docs: README badges + new-option docs, SECURITY.md, issue/PR templates

26 tests passing; build emits ESM+CJS+types.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,19 @@
+# Description
+
+<!-- What does this PR change, and why? -->
+
+## Type of change
+
+- [ ] Bug fix
+- [ ] New feature (pattern preset, provider, …)
+- [ ] Documentation
+- [ ] Tooling / chore
+
+## Checklist
+
+- [ ] Tests added or updated for the change
+- [ ] `npm test` passes
+- [ ] `npm run typecheck` passes
+- [ ] `npm run lint` and `npm run format:check` pass
+- [ ] Docs / CHANGELOG updated if behavior or the public API changed
+- [ ] No runtime dependencies were added to the core