Closes#1944
API 1.3 lets a plugin search the IDE's workspace symbol index. Results are limited to paths the plugin may read under its `project.read` grant (external content roots and symlink aliases excluded), the search honours the call's cancellation and deadline including lock waits, and ranges use UTF-16. Incremental index updates no longer publish symlink-ancestor aliases. Verified on macOS with the test fixture.
Co-authored-by: arnaud-ritti <[email protected]>