Settings: rows read like macOS System Settings rows

[T0mSIlver]

What

Stacked on #199 — this PR targets settings-sidebar-chrome, not main.
Do not delete #199's branch before this one is retargeted; GitHub auto-closes
children when a base branch disappears. Review #199 first.

Presentation-only rewrite of the shared row/group primitives in
SettingsView.swift. Same controls, same bindings, same behavior — rendered in
the row idiom the rest of macOS uses: label leading, control trailing,
explanation on its own full-width line underneath.

The old row put the label in a fixed 128pt column with everything else to its
right. Long labels ("Use Claude Code project files as polish context") wrapped
inside that column while short ones ("Enable") left a gutter, and every help
sentence started at the column's edge — so each card had a second, ragged left
margin. Now the label takes the leftover width (layoutPriority(0), so controls
keep their intrinsic size) and the explanation is a row of its own, aligned to
the label.

Also:

• Page-level .toggleStyle(.switch), so 12 call sites stop repeating it.
• SettingsGroup: corner radius 18 → 8, .quinary fill with a .quaternary
  border, .headline header (down from 17pt semibold), and a Divider() between
  rows.
• The last divider is removed geometrically — the row container is laid out
  1pt short and clipped, so the final divider falls outside the clip. The
  alternative was teaching the card to enumerate its children, which are
  heterogeneous and arrive wrapped in Group/if branches.

Deviations from the brief (with reasons)

1. Help text became a help: parameter — the one call-site change. The brief
   asked for no call-site changes, but most call sites nest the help text inside
   their own VStack, and a row cannot pull a nested view out of its control
   column — which is exactly where this text must not be. The zero-call-site
   alternative is hoisting the string with a PreferenceKey, which puts every
   row's layout one frame behind its content and fights Swift 6's @Sendable
onPreferenceChange (the closure would capture a non-Sendable generic
   View). The migration is mechanical, and it shrinks the call sites — the
   wrapper VStacks disappear.
2. No page-level .controlSize(.mini). Applied at page level it shrinks every
   button, picker, and text field on the page, not just switches — and macOS
   System Settings uses regular-size switches. Says so here rather than shipping
   a pane of miniature buttons; happy to reverse if the owner wants the smaller
   switch specifically.
3. Added layout: .stacked for composite rows (see below). Not in the brief,
   but it is the fix for the exact rows the brief asked me to hand-check.
4. Row label/control alignment stays .top rather than centering: several rows
   have tall controls, and a centered short label beside those reads as
   misaligned.

The composite rows the brief flagged — what I found and did

Hand-check here = careful code reading plus a clean build; none of it has been
seen on screen (see below).

Row	Under trailing alignment	What I did
ShortcutRecorderField + Reset/Clear button (:578-632)	Fine — fixed 132pt field + button is a bounded, intrinsically-sized HStack. The SettingsInlineMessage ("Not set. Record one to enable.") now sits under the control, trailing-aligned, instead of under the label.	Left as-is; validation text belongs next to the control it validates. Flagged for the owner's eye.
Sliders (:558, :651)	Broken. A Slider reports no intrinsic width, so in a trailing column it collapses to nothing.	Both get an explicit SettingsLayout.sliderWidth (190pt) track.
ManagedBackendStatusRow (:386)	Fine — dot + optional progress + short caption.	Unchanged.
ClaudePluginSettingsRow	Broken. Two buttons + spinner + result line ≈ 400pt of control; the label would be squeezed to a wrapped stub.	layout: .stacked.
ClaudeRemoteHostsSettingsRow	Broken, worse — host rows (3 buttons each) plus an enrollment form of two text fields and a button.	layout: .stacked.
SettingsFileNotes ("Included files")	Full-width list of file names, not a control.	layout: .stacked.
PermissionRowsView	Shared verbatim with the onboarding wizard, and the card no longer supplies inner padding.	Wrapped in SettingsGroupRow at the call site rather than modified — onboarding is untouched.
SettingsAvailabilityCard	Same padding issue.	Renders inside SettingsGroupRow; radius 16 → 8.

Every consent-critical help string (the polish-context toggles, the non-local
endpoint toggle) is byte-identical, and the rationale comments that explain each
one moved with them.

Proof

• Unit suite green — ./scripts/remote-build.sh

Test Suite 'localvoxtralPackageTests.xctest' passed at 2026-07-28 00:17:59.858.
	 Executed 2021 tests, with 2 tests skipped and 0 failures (0 unexpected) in 71.535 (71.637) seconds

No new warnings (.build/last-remote.log has only the pre-existing
ClaudePluginInstallService.swift:226 and ClaudeHookPublisherTests ones).

CI build-test on this branch: pass (4m38s). #199 picked up review hardening
after this branch was cut (da5d653, drill scripts only — no app code), so this
branch is one commit behind its base; nothing in it touches the same files.

• AX drill: the drill's needles are group titles ("Permissions", "Polishing",
  "Start dictation with", …) and field labels ("Endpoint", "API key"), all
  unchanged by this PR, and Settings: hand-rolled sidebar chrome in place of the TabView #199's scoped selectors are unaffected. The drill
  could not run tonight — see Settings: hand-rolled sidebar chrome in place of the TabView #199's Proof for the two runs and why (an existing
  app instance on the runner's GUI session would not quit; the guard was not
  weakened).
• LLM lanes: not run, and not required — SwiftUI layout of existing controls.
  Nothing here changes prompts, model pins, sampling, or anything that reaches
  the model; scripts/ci/llm-lane-filter.sh matches nothing in the diff.

UI change — what was verified, and what was not

Verified: clean build under Swift 6.2 strict concurrency, full unit suite, and
the row-by-row reading in the table above.

Not verified — needs the owner's eyes (./scripts/try-pr.sh <this PR>), in
priority order:

1. The Text Processing pane, which has the longest labels and the two stacked
   composite rows: do the toggles line up on the right, and does the explanation
   under each one read as belonging to it?
2. The Dictation pane's two shortcut rows and the 190pt sliders — the two
   spots where I changed geometry on a guess.
3. That the group cards show a divider between every row and no stray line
   above the bottom edge (the 1pt clip trick).
4. That .quinary on .windowBackgroundColor is still visible as a card in both
   light and dark appearance.