refactor: reorganize client transport and extension internals

- Split client, native, remote, serve, markdown, and SDK internals into focused packages with direct imports.
- Move local and remote transport framing/protocol helpers behind clearer module boundaries.
- Break up the extension injected DOM logic into a separate content dispatch bundle and dedicated content modules.
- Add explicit client handling for passive remote discovery without noisy PQ warnings.
- Keep behavior covered with updated unit, integration, and extension tests.

package.json

@@ -3,9 +3,9 @@
   "private": true,
   "type": "module",
   "scripts": {
-    "build:extension": "esbuild extension/src/index.ts --bundle --format=iife --target=chrome120 --outfile=extension/background.js",
+    "build:extension": "esbuild extension/src/index.ts --bundle --format=iife --target=chrome120 --outfile=extension/background.js && esbuild extension/src/content-dispatch.ts --bundle --format=iife --target=chrome120 --outfile=extension/content-dispatch.js",
     "build:tests": "esbuild extension/test/*.test.ts --bundle --format=esm --platform=node --outdir=extension/test-dist --out-extension:.js=.mjs",
-    "test:extension": "npm run build:tests && node --test extension/test-dist/*.test.mjs",
+    "test:extension": "npm run build:tests && node --disable-warning=ExperimentalWarning --test extension/test-dist/*.test.mjs",
     "check:extension": "tsc -p tsconfig.json --noEmit && npm run build:extension && node --check extension/background.js && npm run test:extension"
   },
   "devDependencies": {