Adds a Fonts section to Appearance with four client-persisted
preferences — interface (sans), composer, code, and terminal font
families. Family only; sizing is deliberately left for a follow-up.

- contracts: four FontFamilyPreference client settings (empty string
  means default), patchable per key
- the font theme tokens move out of the inline Tailwind theme so
  utilities reference the variables, and a FontAppearanceSync applies
  custom families as CSS variable overrides with the default stacks
  kept as fallbacks
- the composer gets its own --font-composer variable (defaults to the
  sans stack) applied on the editor surface, so prompt writers can use
  a mono face without changing the rest of the app
- the terminal preference feeds the Ghostty surface's font option and
  live setFont from pingdotgg#4860's groundwork; the bundled Nerd Font symbols
  fallback keeps prompt glyphs on any custom face
- each settings row shows a live preview rendered in the resolved
  stack, with per-row reset; custom names are normalized and quoted
  through tested pure helpers

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…views

Replaces the free-text family inputs with dropdowns of curated faces
filtered through document.fonts.check so only fonts that will actually
render are offered (bundled webfonts always appear); a Custom… option
keeps arbitrary families possible. Each option renders in its own face,
and every row gains a preview card styled like the real surface — chat
text, a mini composer, a highlighted code snippet, and a dark terminal
prompt — rendered in the resolved stack, matching mobile's Appearance
screen style.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…views

document.fonts.check() answers true for families that are not installed
(nothing needs loading), so the dropdowns offered fonts that silently
fell back to the default stack and the sans-side previews appeared not
to update. Availability now comes from canvas metric probing: a family
counts as available when substituting it before a generic changes the
measured advance.

The terminal preview card also follows the app theme now — the real
terminal renders on the app background in light mode, so a hardcoded
dark card was inconsistent theming.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Client settings hydrate after mount, which dropped two things on reload: the
terminal font (setFont fired while the surface was still loading, so the
preference never reached the created terminal) and the custom-font input
(customMode initialized from the pre-hydration empty value, leaving the
field hidden behind a "Custom" trigger). The terminal re-applies the current
preference once the surface exists, and the input visibility now derives
from the value itself.

Also groups mixed dropdowns (composer) into labeled Sans serif / Monospace
sections and removes the composer's redundant default entry - the reset
affordance already returns it to following the interface font.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…om names

Every font dropdown now offers the full catalog split into bold Sans serif /
Monospace sections, so any surface can point at any face. The custom input
edits a draft that only commits once the typed name probes as an installed
font - the current font holds (and the field flags invalid) while a partial
or unknown name is typed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Per review direction the interface and code fonts stay on the theme
defaults; only the prompt textarea (people who prefer writing prompts in a
mono face) and the terminal remain configurable. The textarea setting is
retitled to make its scope explicit - the rest of the composer follows the
interface font.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

An emptied custom font field now resets the preference to the default
instead of silently keeping the previous font behind an empty-looking
input; partial or unknown names still hold the current font while typing.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Selecting Custom no longer prefills the outgoing family, so the field is
ready to type into; the applied font holds until a valid name is entered,
and an empty field is not flagged as invalid.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Four rows all opening with "Used ..." read like a filled-in template and
restated their own titles. Each line now just names what it covers, and the
prompt row carries the reason people actually asked for it.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…grows it

The branch, workspace, and environment controls sit in a fixed-width strip,
so a larger interface font pushes their labels into each other. The strip is
now a query container and the labels hide below a rem-based threshold -
rem scales with the interface size, so the controls fall back to their icons
exactly when the text would start to overlap, at any font size or window
width.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…labels only on overflow

The terminal and code views render on a fixed cell grid, so a proportional
face like Helvetica Neue cannot line up - their pickers now offer monospace
faces only, while the interface and prompt keep the full catalog.

The composer strip's labels collapsed at a guessed container width, which
hid them even when they fitted. It now measures how far each label is
clipped and collapses only once they genuinely stop fitting, remembering the
required width so hiding them cannot flip the decision back.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

A proportional family draws each glyph on its own advance while the cursor
and selection sit on the grid's single cell width, so the text drifts left
of its cells and the cursor strands to the right - the ragged gaps and
misplaced cursor seen with Helvetica Neue.

The renderer now measures the requested family and falls back to the default
when it is not monospace, so a value stored before the picker was restricted
cannot leave the terminal in that state. Unmeasurable environments and
absent faces are treated as monospace, leaving the normal fallback chain in
charge.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The size preference is a ceiling, not an absolute: narrow panes (splits, the
side panel) now shrink the rendered size until a classic 80-column grid
fits, down to a legibility floor, and widening slides it back up to the
preference. The measurement lives in fit(), so pane drags, splits, and
window resizes all pass through it.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…l families

Three review findings:

- The code size preference set --font-size-code but nothing read it. Block
  code and highlighted chat blocks now take it; inline code stays relative to
  its sentence so it cannot tower over the surrounding prose.
- The custom family field autofocused whenever it mounted, so opening
  Appearance with a persisted non-catalog family stole the keyboard. Focus
  now follows the deliberate act of picking Custom from the dropdown.
- The terminal silently falls back from a proportional face, while the row
  still accepted and previewed one. The terminal row now refuses a custom
  family that is not monospace (flagging the field instead of pretending it
  took the value), and its preview renders the fallback the grid will
  actually draw.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…e family

The interactive environment picker rendered a bare SelectValue, so the
overflow measurement never saw it and it stayed full-width while its
neighbours collapsed. It now carries the same label marker and transition.

The Code row accepted any custom family, including proportional faces that
break column alignment in code blocks, diffs, and file previews. It requires
monospace now, matching Terminal.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

…ted labels

Three review findings:

- High: track clicks and keyboard steps fire input and change in one task,
  before any re-render, so the change handler read a stale draft and dropped
  the commit. The draft now mirrors into a ref written inside the input
  handler itself, so the commit reads the same turn's value.
- The global pre font-size rule beat text-size utilities and inherited sizes
  on unrelated pre surfaces (terminal previews, approvals). The code size is
  now scoped to chat markdown code blocks; diffs and file previews already
  take it through --diffs-font-size.
- SelectValue truncates internally, so the outer label marker's scrollWidth
  matched its clipped box and the workspace/environment labels fell out of
  the strip's overflow measurement. The text width is now the largest
  scrollWidth in the label subtree.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

The 16px focused-field floor exists for the touch-browser zoom quirk, which
desktop browsers do not have - a narrow desktop window must not silently
override a smaller chosen prompt size. Gate the media query on a coarse
pointer.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>