[Feature] Endpoint presets

[peterschmidt85]

Problem

Creating a reliable model service requires selecting a model variant, serving configuration, and
hardware, then validating that combination. The result cannot currently be saved and reused as a
local endpoint recipe.

Change

• Add agent-assisted endpoint preset creation and local preset storage.
• Add commands to list, apply, and delete endpoint presets.
• Add endpoint configuration, documentation, and focused coverage for the new lifecycle.

See the Endpoints concept page for the proposed UX.

AI assistance

AI assistance was used for implementation, tests, documentation, and E2E investigation.