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>

.gitignore

@@ -1,3 +1,5 @@
 node_modules/
 dist/
 bun.lockb
+.claude
+.archon