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>

tsconfig.json

@@ -11,5 +11,5 @@
     "noEmit": true,
     "types": ["bun-types"]
   },
-  "include": ["src/**/*.ts"]
+  "include": ["src/**/*.ts", "test/**/*.ts"]
 }