fix: Address review findings (CRITICAL/HIGH)

CRITICAL fixes:
- Stop passing mint URLs as relay URLs in initNDK (protocol mismatch)
- Add unit tests for buildTransactionHistory (dedup, fallback, sort)

HIGH fixes:
- Restore .claude entry in .gitignore
- Add warning logging for skipped malformed proof tags in nutzap parsing
- Add error handling + 30s timeout to NDK initialization
- Add unit tests for formatCSV and escapeField
- Export escapeField for testability

Also: add test script to package.json, include test/ in tsconfig

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -4,7 +4,8 @@
   "type": "module",
   "scripts": {
     "start": "bun run src/index.ts",
-    "type-check": "bunx tsc --noEmit"
+    "type-check": "bunx tsc --noEmit",
+    "test": "bun test"
   },
   "dependencies": {
     "@nostr-dev-kit/ndk": "latest"