chore(deno): finish import extensions for sites/mp-sync paths

- sites/mp-sync relative imports already carry extensions; drop the biome
  useImportExtensions override and --unstable-sloppy-imports in typecheck:deno
- mp-sync scripts: deno shebang (+x), static `import YAML from "yaml"`,
  README/usage switched to `deno run -A`
- verified: check.mjs --to e6820a8 (49 unchanged), movieclaw-import --check (0 diff)

Co-Authored-By: Claude Fable 5.1 <[email protected]>

scripts/mp-sync/build-ledger.mjs

@@ -1,8 +1,8 @@
-#!/usr/bin/env node
+#!/usr/bin/env -S deno run -A
 /**
  * 生成 scripts/mp-sync/ledger.json 与 docs/porting/mp-sync-ledger.md 中的对照总表。
  *
- *   node scripts/mp-sync/build-ledger.mjs [--mp /opt/moviepilot-plus/upstream/MoviePilot] [--commit e6820a8]
+ *   deno run -A scripts/mp-sync/build-ledger.mjs [--mp /opt/moviepilot-plus/upstream/MoviePilot] [--commit e6820a8]
  *
  * 数据来源:源码文件头 `@mp-source <上游路径> @ <提交>` 标签 + ledger.manual.json(未打标签的既有移植)。
  * 每条记录保存移植时的上游提交与该文件内容 sha256,供 check.mjs 比较。