feat(p0): add favorite folder sync and sqlite data foundation

Implement P0 of the reaction dashboard: config loading with hot reload, SQLite migrations with backups, single-writer queue, read-only Bilibili fav client, folder import/diff sync, invalid-resource handling, blacklist seed, scheduler, and JSON redacted logging. Includes offline unit and transport-level contract tests; all existing and new tests pass.

.gitignore

@@ -0,0 +1,17 @@
+# 本地凭据，绝对不要提交
+config.json
+config.json.bak
+config.json.tmp
+
+# 计划 / 日志 / 快照
+data/
+*.journal.jsonl
+
+# Python
+__pycache__/
+*.pyc
+.venv/
+
+# uv / test tooling cache
+.uv/
+.pytest_cache/