Three fixes to the settings surface.
The default never reached settings.yaml. The api-proxy keeps an explicit
allowlist of settings namespaces it exposes to configuration clients, and
`agent-presets` was never added — so both pickers moved and then silently
forgot, which is worse than refusing the control. The host seam was fine all
along; only the wire boundary refused. The regression test fails with the
namespace removed.
The nav row showed the fallback gear and read `Agent preset` in Chinese,
matching neither sibling (通用设置 / 模型). It is now 智能体 with the think
glyph, the only unused icon in the set whose semantics point at the agent
rather than at tuning sliders (Personalization is already the workspace
browser's filter control).
A composition is a file, but "edit it on the filesystem" is not a browser
affordance. The roster gains `read`/`write`/`remove` beside `select`, and
the browser gains a settings section over them: the presets as rows, one
composition open in a YAML editor at a time, and per-row default, duplicate,
and delete.
All four authoring methods are loopback-pinned. A composition names the
plugins a session runs, so reading one is reconnaissance, writing one is
arbitrary capability, and selecting one can move a session onto a preset
that edits the live runtime. `agentPreset.list` deliberately stays ordinary
and now reports `authorable`, so a surface knows whether creating is
possible at all rather than offering a button whose save always fails.
Authoring starts by duplicating: a shipped preset opens read-only because
the deployment's copy is what a broken local one is compared against. Ids
are contained before they become directory names, and the text is parsed
with the loader's own schema, so a save cannot leave a file no session
could load.
Fixes a defect the real-composition test found: a preset written under the
user's home could never mount, because the loader resolves a row against the
composition's own directory and Node's `node_modules` walk from there never
reaches the installed harness. The mount now records the host base and sends
bare specifiers there, leaving relative paths resolving from the preset.
Also closes the coverage the earlier surfaces in this stack shipped without —
the General row, the composer seat, and the plugin halves now have tests.
A seat in the composer tool row, left of the model select, showing the preset
THIS session runs — its own recorded one, not the deployment default, because a
resumed session runs what it was created with. `SessionSummary` carries
`agentPreset` for that, alongside `cwd` and `origin`.
The switch exists only while the conversation has not started. After the first
turn the seat becomes a plain label rather than a disabled menu: a greyed
control reads as "temporarily unavailable", when in fact the choice is gone for
good. The seat never asks in that state, and the host refuses independently
with `agent-preset-locked`, so a stale client cannot slip one past it.
A rejected switch restores the previous value and surfaces the host's message
rather than leaving the seat showing something the session is not running.
One settings row picking which preset new sessions are composed from.
It is deliberately a new-session preference, not a live switch: a session's
preset is fixed at creation and the host refuses to adopt an existing session
under a different one, so the row says "applies to sessions you start from now
on" rather than implying it can retune a running agent.
Options and the current value come from one `agentPreset.list` call — the
roster already reports which id an unspecified session gets, so the row needs
no settings-schema introspection, unlike the permission row it is modelled on.
The write targets only the namespace's `default` field.
The menu marks `user` rows: a locally authored preset is exactly as privileged
as the plugins it names, and presenting it identically to a shipped one would
hide that.
An empty roster reads as `unavailable` and renders nothing, because composing
no presets is a valid deployment rather than a failure — distinct from a
roster call that failed, which surfaces its message.
