[Improve] Make task workflows searchable by purpose

[roomote-roomote]

​Opened on behalf of @mrubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

• Added a concise plain-language description to every workflow already exposed in the task chat command picker.
• Made those descriptions searchable, so queries such as dependency upgrades find /update-dependencies without requiring the command name.
• Kept command selection and invocation behavior unchanged, with focused coverage for description rendering, intent-based filtering, and exact command insertion.

Why this change was made

Users keeping reusable agent instructions in scattered text files signals that prompt and workflow reuse remains hard to discover. Open work already covers saved prompts, unfinished drafts, original-prompt copying, Discord starters, and automation navigation, so this change addresses a smaller complementary gap: understanding and finding workflows that Roomote already ships.

Impact

Users can discover an appropriate workflow from its purpose while composing a task follow-up instead of memorizing slash-command names. The change is limited to the existing command picker and does not alter workflow routing or execution.

Validation

• Focused CommandSearch client tests pass (4 tests).
• Web TypeScript checking and ESLint pass.
• Repository pre-push checks pass: oxlint, residual lint, fast type checks, and knip.
• Browser proof was attempted, but the seeded local account redirected into inference-provider setup before an existing task composer was reachable; no screenshots are attached.

Non-goals

• No new prompt library, template catalog, persistence, or backend schema.
• No changes to saved-prompt, draft-recovery, prompt-copying, Discord, or custom-automation work already covered by open pull requests.
• No changes to workflow routing, execution semantics, or task launch behavior.

[roomote-community]

No code issues found. See task

_{Reviewed de58d2f}