feat: updated capabilities and save modal flow

[vinit-truefoundry]

---

Note

Medium Risk
Touches agent write APIs and atomic session coupling (403/404/422 paths), plus a large Save Agent and composer interaction surface where stale spec or flush timing could cause wrong payloads.

Overview
API & SDK: Agent create/update bodies can include optional session_id to update a mutable inline session in the same request; responses may return session_updated_at. OpenAPI also documents redacted-secret PUT semantics for API keys and MCP headers, richer MCP read shapes (auth, auth_status), model list provider, and moves shipped presets from /settings/*/catalog to /api/v1/catalog/*. Session listing is documented as sorted by updated_at with keyset page_token.

Harness / builder: saveAgent sends session_id when provided, returns sessionUpdatedAt, and relies on explicit create/update intent (no pre-save agent list lookup).

UI SDK: Save Agent opens a review modal after flushing the runtime spec: name, instructions, summary rows for model/MCP/skills, capability toggles, and stacked editors reusing shared catalog panels. Successful save calls adoptAgentSpec with the persisted timestamp and rebinds the mutable shell agent. The draft composer uses a Tools (N) control (connectors, skills, capabilities tab), a separate attach button, shared Switch and DraftCatalogProvider nesting, and DraftCatalogProvider at the app shell for Save Agent editors.

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[linear]

AGE-1778 Save Agent + Capabilities in the Composer Selector

https://preview--trueforge.lovable.app/

Ask chiragjn how to store capabilities in the AgentSpec

Review in Linear

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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