Create SimpleChat FAQ agent seeded from official docs

## Summary
Create an admin-only or optionally user-facing SimpleChat FAQ agent that answers questions about the app using official docs and can optionally create support tickets.

## User Value
Tracking this as a GitHub issue moves the backlog item out of a private markdown file and gives the team a clear place to prioritize, design, implement, and validate the work.

## Proposed Behavior
Seed a public workspace from docs markdown, create an agent with assigned knowledge, disable broad web search/image generation by default, and optionally attach a ServiceNow action for ticket creation.

## Acceptance Criteria
- [ ] The requested behavior is designed or implemented for the relevant SimpleChat surfaces.
- [ ] Permission, configuration, and existing-feature interactions are accounted for.
- [ ] Tests, documentation, or validation notes are added as appropriate.

## Notes
- Source backlog entry: SimpleChat Self-Help / FAQ Agent
- Source file: priv-simplechat-2/grouped_feature_fix_backlog.md
- Backlog status: New / Extension
- Current anchors: Public Workspaces, Assigned Knowledge, SimpleChat native plugin, docs content under `docs/`
- Proposed roadmap priority: P2
- Proposed roadmap size: M