Context files, hybrid search, and agent steering

Features

• Context files and hybrid search (AUX-179): Introduced get_context_file tool and rune-safe list previews, chunk-level embeddings, hybrid search, and a full suite of structured context-file tools for agents.
• MCP catalog editorial metadata: Added editorial metadata and improved surfacing of MCP servers in the catalog browser.
• Agent steering: Delivered cancel-preserving output with steering messages, fixed steering behavior mid-turn, corrected context formatting, and resolved partial GPU cancel issues.

Improvements

• Context-file agent picker: Modal agents now use the settings list, filter by team, and expose team_id on the agent list; Admin Agent is excluded from the picker.

Fixes

• Connector reliability: Fixed anonymous reply tools, restored image vision support for Slack and Discord, and corrected DM threading behavior.
• Chat turn indicators: Failed turn indicators are now persisted correctly across sessions.
• Chat worker errors: Worker errors now fail without retry instead of looping indefinitely.
• MCP catalog: Removed internal badges that were incorrectly surfaced in the public catalog view.

Internal

• Stopped persisting the system prompt in dispatch_snapshot to reduce snapshot size.