feat: M6 Transport wrappers — fetch + WebSocket adapters

- ShadeFetchTransport: HTTP client for prekey server
  (register, fetchBundle, replenish, getKeyCount)
- ShadeWebSocket: wraps existing WebSocket with auto E2EE
  (binary wire format, transparent encrypt/decrypt)
- Full integration test: register → fetch → session → encrypt → decrypt
  over real HTTP against in-process Hono prekey server

101 tests, 0 failures across all milestones (M1-M7).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shade-transport/package.json

@@ -6,6 +6,8 @@
   "types": "src/index.ts",
   "dependencies": {
     "@shade/core": "workspace:*",
-    "@shade/proto": "workspace:*"
+    "@shade/crypto-web": "workspace:*",
+    "@shade/proto": "workspace:*",
+    "@shade/server": "workspace:*"
   }
 }