chore(deps): bump typescript ^5.4.0 → ^6.0 (#8)

## Summary
- Bump `typescript` `^5.4.0` → `^6.0` (resolves to 6.0.3). TS 6 is the
transitional cleanup release ahead of TS 7 (the Go-native compiler) —
mostly turns 5.x deprecations into errors.
- `tsc --noEmit` passes clean with no source changes.
- Added `"ignoreDeprecations": "6.0"` to `tsconfig.json`: `tsup`'s DTS
build internally sets `baseUrl` (deprecated in 6.0, stops functioning in
7.0), which makes `tsup --dts` error out and emit **no `.d.ts` files** —
a regression for a published SDK. `ignoreDeprecations: "6.0"` is the
TS-team-recommended interim silencer (see https://aka.ms/ts6); drop it
once `tsup` stops injecting `baseUrl`.
- Verified: `npm run typecheck` ✅, `npm run build` (ESM + CJS + **DTS**)
✅ — `dist/index.d.ts` emitted.

## Test plan
- [x] `npm run typecheck` clean
- [x] `npm run build` produces ESM + CJS + `.d.ts`
- [ ] CI green
- [ ] (npm publish is gated separately — version bump not included here)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: Mlaz-code

package-lock.json

@@ -55,7 +55,7 @@
   "devDependencies": {
     "@biomejs/biome": "2.4.12",
     "tsup": "^8.0.0",
-    "typescript": "^5.4.0",
+    "typescript": "^6.0.3",
     "vitest": "^3.0.0"
   }
 }

package.json

@@ -4,6 +4,7 @@
     "module": "ESNext",
     "moduleResolution": "bundler",
     "lib": ["ES2020", "DOM"],
+    "ignoreDeprecations": "6.0",
     "strict": true,
     "esModuleInterop": true,
     "skipLibCheck": true,