Migrate LSP client to vscode-jsonrpc for improved stability (#1095)

* refactor(lsp): migrate to vscode-jsonrpc for improved stability

Replace custom JSON-RPC implementation with vscode-jsonrpc library.
Use MessageConnection with StreamMessageReader/Writer.
Implement Bun↔Node stream bridges for compatibility.
Preserve all existing functionality (warmup, cleanup, capabilities).
Net reduction of ~60 lines while improving protocol handling.

* fix(lsp): clear timeout on successful response to prevent unhandled rejections

---------

Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>

bun.lock

@@ -18,6 +18,7 @@
         "jsonc-parser": "^3.3.1",
         "picocolors": "^1.1.1",
         "picomatch": "^4.0.2",
+        "vscode-jsonrpc": "^8.2.0",
         "zod": "^4.1.8",
       },
       "devDependencies": {
@@ -303,6 +304,8 @@
 
     "vary": ["vary@1.1.2", "", {}, "sha512-BNGbWLfd0eUPabhkXUVm0j8uuvREyTh5ovRa/dyow/BqAbZJyC+5fU+IzQOzmAKzYqYRAISoRhdQr3eIZ/PXqg=="],
 
+    "vscode-jsonrpc": ["vscode-jsonrpc@8.2.1", "", {}, "sha512-kdjOSJ2lLIn7r1rtrMbbNCHjyMPfRnowdKjBQ+mGq6NAW5QY2bEZC/khaC5OR8svbbjvLEaIXkOq45e2X9BIbQ=="],
+
     "which": ["which@2.0.2", "", { "dependencies": { "isexe": "^2.0.0" }, "bin": { "node-which": "./bin/node-which" } }, "sha512-BLI3Tl1TW3Pvl70l3yq3Y64i+awpwXqsGBYWkkqMtnbXgrMD+yj7rhW0kuEDxzJaYXGjEW5ogapKNMEKNMjibA=="],
 
     "wrappy": ["wrappy@1.0.2", "", {}, "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ=="],