refactor!: replace snapshot with reader fallback, collapse commands

Remove the snapshot command and enhance reader to try Firefox Reader
View first, falling back to raw Turndown conversion of document.body
when Reader View fails or is skipped via --no-reader.

- reader always returns markdown by default (--format=json for structured)
- JSON output includes method: 'reader' | 'raw' to signal extraction path
- --no-reader skips Reader View (stays on loaded page, preserving JS mutations)
- Add @ts-nocheck to test/smoke.js and exclude test/ from tsconfig
- Update all tests from snapshot to reader with --no-reader for data URIs
- Update AGENTS.md and help text

BREAKING CHANGE: snapshot subcommand removed; use reader instead.

tsconfig.json

@@ -11,5 +11,6 @@
     "forceConsistentCasingInFileNames": true,
     "skipLibCheck": true
   },
-  "include": ["src/**/*.ts"]
+  "include": ["src/**/*.ts"],
+  "exclude": ["test", "node_modules", "dist"]
 }