Add remote script loader with intelligent completions

Features:
- Remote script execution with version control (name@ref)
- Background daemon for fast completions (< 15ms)
- HTTP caching with ETag/Last-Modified support
- Context-aware completions with async support
- Comprehensive documentation and type definitions

Changes:
- Add loader.ts with daemon mode
- Add completions.d.ts type definitions
- Add COMPLETIONS.md guide for developers
- Add README.md with usage examples
- Update configure_ssh_key.ts with async completions
- Use JSR imports for remote execution compatibility

deno.json

@@ -6,5 +6,10 @@
   },
   "tasks": {
     "configure": "deno run --allow-read --allow-write --allow-run --allow-env configure_ssh_key.ts"
+  },
+  "lint": {
+    "rules": {
+      "exclude": ["no-external-import"]
+    }
   }
 }