plugin(telemetry-watcher): inline plugin SDK to break ESM TS chain

@fusion/plugin-sdk's package.json points its import entry at
src/index.ts (TS source), and that file imports core/src/plugin-types.js
via relative path. Node 22 ESM has no TS loader so the chain
unraveled at runtime: the plugin loader successfully resolved our
compiled dist/index.js, but the very first `import { definePlugin }
from "@fusion/plugin-sdk"` walked into TS source and fell over.

definePlugin is a pure typed identity function — it adds no runtime
behavior. Inline its source plus a structural copy of the plugin
context/route/manifest types we use, drop the @fusion/plugin-sdk
dependency entirely. The compiled output now imports nothing outside
node:crypto and Node builtins, so it can load anywhere fusion can
spawn ESM modules.

When fusion publishes a compiled SDK build, swap the inline types
back to import statements and restore the workspace dependency.

plugins/fusion-plugin-telemetry-watcher/package.json

@@ -17,9 +17,6 @@
     "build": "tsc",
     "test": "vitest run --silent=passed-only --reporter=dot"
   },
-  "dependencies": {
-    "@fusion/plugin-sdk": "workspace:*"
-  },
   "devDependencies": {
     "@types/node": "^25.5.2",
     "typescript": "^5.7.0",