feat(ui): rework the settings drawers, plugin panel and add-model list - #700

#700)

## Summary

A pass over the settings dialog's drawers, the plugin page and the model
provider page, plus one composer layout fix. Frontend only: no RPC or
backend change.

**Row drawers (tools, plugins, chat parameters).** A drawer is the same
table indented one step and tied to its row by a rail, instead of a
bordered
card inside the card. Its controls line up with the row's own control
edge
and are one size (28px / 12px). The old rule that claimed this step down
never applied: it named `.settings-mini`, a class no markup carries, so
it
and eight sibling rules were dead and are removed. The chat parameters
disclose through the page's own fold (`.foldcap`) and read out their
values
while closed; the context window's value and mode share one row. An open
row
gives up its separator (opening one used to make a line appear between
the
row and its own drawer, because the row stopped being `:last-child`).
The
add-a-provider box keeps its box on rules scoped to both classes, which
it
previously lost to the drawer's later, equal-specificity rules.

**Plugins.** The drawer now shows what the runtime row and the catalogue
entry already carried and the page dropped: the credential, the address,
the tool names, and the connection manager's own error text. A server
the
catalogue has no entry for is no longer told "this server takes no
credential" (github hit this with an expired token); the offline
fixture's
catalogue ids and auth modes now match its rows. "Connection failed" is
a
static status chip; reconnect moved into the drawer, first, beside the
reason.

**Model providers.**
- The add-model popover lists only models not yet added, is
tick-then-add
(one `model.add_models` call for the ticked set), and has a select-all
per
vendor group and one for everything shown. Previously each click wrote
one
  model and reloaded every configured provider twice.
- Rows and chips name a model without the provider's own prefix (full id
in
the title), and a gateway's live list groups by vendor rather than under
  the gateway's own name.
- The configured-model chips fold past eight; the fold state lives in
the
  store so a removal does not collapse it.
- One outbound link per page (the name's arrow opened the same key page
as
"Get a key"). Fields are one width with their buttons on the pane's
right
  edge. A keyless local provider no longer shows "Server address" twice.
- Controls inside a section label no longer inherit its bold (the "Add
  model" button was weight 600).

**Composer.** `dockLift` measures every direct child of the dock rather
than
a class list, so the running-task chip moves the transcript up instead
of
covering its last lines.

Copy: `gui.settings.roles.chat_use` now says it is the default
configuration
for new sessions. Unused keys (`ctx_current`, `plugins.auth`,
`plugins.failed_retry`, `model.add_all`, `model.add_group`,
`providers.showing_added`) are removed and the TUI catalogue
regenerated.

## Type

- [ ] Fix
- [x] Feature
- [ ] Docs
- [ ] CI / tooling
- [ ] Refactor
- [ ] Other

## Verification

Run on the branch after rebasing onto `main` (5b3788d):

- `npm run gen:check --prefix ui-web`: generated.ts matches the contract
- `npm run type-check --prefix ui-web`: clean
- `npm run lint --prefix ui-web`: 0 errors (4 pre-existing warnings in
other files)
- `npm test --prefix ui-web`: 206 files, 2854 tests passed
- `npm run lint:i18n --prefix ui-tui`: generated catalogue is up to date

New tests: `scripts/gates/settings-drawer-css.test.mjs` (stylesheet
facts
jsdom cannot see, including that every `.settings-cfg .X` rule targets a
class the markup carries), `features/composer/store.dockLift.test.ts`
(stubs
rects and asserts the measured value), and cases in `Roles.test.tsx`,
`Plugins.test.tsx`, `ProviderDetail.test.tsx`. Each new assertion was
mutation-checked: the change was reverted in place and the test failed.

Checked in a real browser against the offline fixtures and against a
live
local gateway (settings read, models ticked but never added): widths,
alignment, weights and tick latency (30-46 ms, no RPC per tick) measured
with `getComputedStyle` / `getBoundingClientRect`.

- [x] Relevant tests pass locally
- [x] Relevant lint / type checks pass locally
- [ ] User-facing docs or screenshots are updated when needed

No user docs describe these screens.

## Risk

- [x] Security impact considered
- [x] Backward compatibility considered
- [x] Rollback path is clear for risky changes

User-visible: the add-model popover no longer removes models (the chips'
`x` on the provider page does, with the same in-use refusal), and a
click on
a row ticks instead of writing. No stored data or wire shape changes;
the
settings source's `serverAuthFields` became `serverDetail` inside the
page
only. Rollback is reverting this commit.

## Related Issues

N/A

---------

Co-authored-by: arelchan <204152633+arelchan@users.noreply.github.com>
Co-authored-by: Claude (claude-opus-5-5) <noreply@anthropic.com>