fix(browser): allow inbound media uploads

Allow the browser upload tool to resolve OpenClaw-managed inbound media refs such as `media://inbound/<id>` and sandbox-relative `media/inbound/<id>` while preserving the existing upload-root path contract.

Keep upload-root files ahead of sandbox-relative inbound fallback, reject nested absolute inbound media files, and validate raw `media://` paths before URL normalization so traversal-shaped refs cannot resolve to direct media ids.

Verification:
- `OPENCLAW_VITEST_MAX_WORKERS=1 node scripts/run-vitest.mjs extensions/browser/src/browser/paths.test.ts --reporter=verbose`
- `OPENCLAW_VITEST_MAX_WORKERS=1 node scripts/run-vitest.mjs extensions/browser/src/browser/paths.test.ts --reporter=dot`
- `OPENCLAW_HEAVY_CHECK_LOCK_SCOPE=worktree node scripts/run-tsgo.mjs -p test/tsconfig/tsconfig.extensions.test.json --incremental --tsBuildInfoFile .artifacts/tsgo-cache/extensions-test.tsbuildinfo`
- `pnpm lint --threads=8`
- `.agents/skills/autoreview/scripts/autoreview --mode branch --base origin/main`
- `git diff --check`
- GitHub PR checks on be08e6c8a8: dependency-guard, check-lint, check-test-types, check-additional-extension-bundled, checks-fast-contracts-plugins-a, checks-fast-contracts-plugins-b all passed.

Fixes #83544.

Co-authored-by: Zee Zheng <zheng.zuo0@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

extensions/browser/src/browser-tool.runtime.ts

@@ -48,7 +48,7 @@ export {
 } from "./browser/client.js";
 export { resolveBrowserConfig, resolveProfile } from "./browser/config.js";
 export { DEFAULT_AI_SNAPSHOT_MAX_CHARS } from "./browser/constants.js";
-export { DEFAULT_UPLOAD_DIR, resolveExistingPathsWithinRoot } from "./browser/paths.js";
+export { resolveExistingUploadPaths } from "./browser/paths.js";
 export { getBrowserProfileCapabilities } from "./browser/profile-capabilities.js";
 export { applyBrowserProxyPaths, persistBrowserProxyFiles } from "./browser/proxy-files.js";
 export {