feat(leads): add lead pipeline, keyword/status mapping, and encoding fixes

- Add lead ingestion, review queue, and keyword/status management
- Add DB schema: leads, service_keywords, lead_statuses, processed_messages
- Add migration with default keyword/status seeding per client
- Fix SQLite read/write deadlock in sanitizeEncoding
- Fix UTF-8 corruption: replace byte-iterating replaceAll with strings.ReplaceAll
- Add utf8.ValidString guard to decodeLatin1 to avoid double-encoding
- Remove hardcoded internal-secret; use config.InternalSecret() everywhere
- Add .gitignore for binaries, SQLite DBs, build artifacts, WhatsApp sessions

apps/go-crm/.gitignore

@@ -0,0 +1,45 @@
+# Binaries
+/go-crm
+/main
+/migrate
+/go-crm-test
+*.exe
+*.dll
+*.so
+*.dylib
+
+# Build artifacts
+tmp/
+*.out
+*.log
+build-errors.*
+
+# SQLite databases
+data/
+.dev-data/
+*.db
+*.db-journal
+*.db-shm
+*.db-wal
+*.db.bak
+
+# Test output
+*.test
+*.cover
+*.cov
+coverage/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# WhatsApp session files (if ever synced here)
+.wwebjs_auth/
+.wwebjs_cache/