The web dashboard only showed a read-only "Reasoning" capability badge
with no way to set the effort level — unlike the desktop app, which has
an effort radio in its composer model menu. This adds a picker so the two
surfaces reach parity.
- ReasoningPicker: a Select rendered in the chat sidebar, gated on the
effective model's supports_reasoning capability (from /api/model/info).
Reads/writes agent.reasoning_effort via the existing config REST
endpoints (read-modify-write, the dashboard's single-key save pattern),
so the value lands in the config the agent boots a fresh chat from.
Options mirror the desktop: Off/Minimal/Low/Medium/High/Max.
- ChatSidebar: capture supports_reasoning from the model-info fetch and
render the picker; on change, show the same 'apply on /new or reload'
notice the model switch uses.
- reasoning-effort.ts: DOM-free helpers (normalizeEffort + options) so the
node-env vitest harness can cover the resolution logic, plus tests.
