fix(cursor): discover and preserve native slash commands - #10796

What Changed

Cursor advertises native slash commands such as /goal over ACP, but T3 ignores that catalog. T3 also appends a runtime-info text block that prevents Cursor from parsing the original command correctly.

Publish available_commands_update in the existing workspace catalog and preserve leading slash prompts when sending them to Cursor. Keep local skills and T3's /compact entry, replace withdrawn commands, and isolate catalogs by workspace and provider instance. The workspace cache is bounded to 16 entries.

Command dispatch does not wait for catalog discovery. Cursor can publish metadata after session startup; a first-turn command must still reach its native parser unchanged. Autocomplete gains the native entries once the session advertises them.

Why

Cursor CLI 2026.09.02-c22c1a3 joins ACP text blocks before resolving a leading slash command. Appending <runtime_info> can turn that context into command arguments or prevent a match. Ordinary prompts retain the existing runtime context.

Related to the capability and invocation work in discussion #6766. This is scoped to the existing Cursor adapter, with no client component or contract changes.

Verification

• 46 focused tests pass. The three original regressions fail on upstream 061543e9. A separate regression verifies dispatch before command metadata arrives.
• Server typecheck, targeted lint, formatting, and git diff --check pass.
• Real Cursor through the patched T3 driver: /copy-request-id returns its native response without inference. A /goal task repairs a Python function and passes seven independently checked cases; the test file is unchanged.
• The web client shows the advertised /goal entry and inserts it on selection.

vp test run apps/server/src/provider/Drivers/CursorCommands.test.ts apps/server/src/provider/Drivers/CursorDriver.test.ts apps/server/src/provider/Layers/CursorAdapter.test.ts apps/server/src/provider/acp/CursorTransportFailure.test.ts
# From apps/server:
tsc --noEmit

Longer live sequences can still return Error: RetriableError: WritableIterable is closed. The same workload reproduces this with direct Cursor ACP, without T3. That existing Cursor failure is outside this fix; this PR does not claim full CLI goal-loop parity.

UI Changes

Both captures use Cursor Auto after session startup. The baseline's transport diagnostic is the separate failure described above.

Before	After

8-second command selection recording

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for the command menu
• I included a video for the interaction change
• Review assets are uploaded to GitHub, not committed

Model: GPT-6. Harness: Codex.

Summary by CodeRabbit

• New Features
  • Added support for discovering and displaying Cursor slash commands within workspaces.
  • Preserved typed slash commands and leading commands while command catalogs load.
  • Kept commands and skills isolated across workspaces and sessions.
  • Preserved local skills while updating available Cursor commands.
  • Improved handling of native slash commands when sending prompts.