fix: use dts-bundle-generator for SDK type generation in typecheck

The SDK build:types script was using plain tsc which generated nested type
files (sdk/dist/sdk/src/*.d.ts) instead of a bundled index.d.ts. This caused
TypeScript module resolution failures in CI when packages tried to import
@codebuff/sdk.

Changes:
- Updated SDK build:types to use dts-bundle-generator for bundled types
- Added pretypecheck hooks to npm-app and evals packages
- This ensures SDK types are properly built before dependent packages typecheck

The bundled approach matches the SDK's actual build script and correctly
outputs dist/index.d.ts as expected by package.json types field.

Author: brandonkachen

evals/package.json

@@ -11,6 +11,7 @@
     }
   },
   "scripts": {
+    "pretypecheck": "cd ../sdk && bun run build:types",
     "typecheck": "tsc --noEmit -p .",
     "test": "bun test",
     "test:manifold": "bun test manifold.test.ts",

npm-app/package.json

@@ -19,6 +19,7 @@
     "codebuff": "dist/index.js"
   },
   "scripts": {
+    "pretypecheck": "cd ../sdk && bun run build:types",
     "typecheck": "tsc --noEmit -p .",
     "build": "bun run scripts/build-binary.js codebuff $(node -p \"require('./release/package.json').version\")",
     "release": "bun run scripts/release.js",

sdk/package.json

@@ -23,7 +23,7 @@
   ],
   "scripts": {
     "build": "bun run scripts/build.ts",
-    "build:types": "tsc -p tsconfig.build.json",
+    "build:types": "bunx dts-bundle-generator -o dist/index.d.ts --no-check --export-referenced-types=false src/index.ts",
     "build:verify": "bun run build && bun run smoke-test:dist && bun run test:cjs && bun run test:esm && bun run test:ripgrep && bun run test:tree-sitter-queries",
     "test:typecheck-strict": "tsc --noEmit --strict dist/index.d.ts",
     "smoke-test:dist": "bun run smoke-test-dist.ts",