feat(rpc): add target policy, protocol schemas, and tagged errors

- Add normalizeLoopbackTarget() with loopback-only URL validation
- Add JSON-RPC response decoder with schema validation
- Define 8 tagged errors using Data.TaggedError
- 20 tests covering target policy and protocol decoding
- Re-export all public types from index.ts

web/packages/rpc/package.json

@@ -13,6 +13,11 @@
     "test": "vitest run",
     "typecheck": "tsc -p tsconfig.json --noEmit"
   },
-  "dependencies": { "effect": "3.21.4" },
-  "devDependencies": { "vitest": "4.1.9" }
+  "dependencies": {
+    "effect": "3.21.4"
+  },
+  "devDependencies": {
+    "@types/node": "26.1.0",
+    "vitest": "4.1.9"
+  }
 }