Size every icon on TDesign's scale: four rem tokens, whole pixels

TDesign draws its glyphs on a 24px grid with a 2px stroke and sizes a
component's icon 2px above its text, in whole pixels. The templates had
drifted to 12 one-off sizes, most of them fractional (0.9rem = 14.4px), so
strokes blurred and neighbours never matched: the tab bar's 14.4px cog
beside a 12.8px +, the shortcut rows' 12px + beside an 11.2px reset and
9.6px chip x.

Every <ng-icon> now takes one of --icon-size-sm (14px: beside 11-12px
text, small icon buttons), -md (16px: file rows, window titles, path-bar
buttons), -lg (20px) or -xl (24px: lone spinners and status marks).
--action-icon goes; architecture.md and gotchas.md carry the rule.

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

docs/architecture.md

@@ -507,7 +507,12 @@ none`, a drawn check / square dot), selects (a `currentColor` caret; use
 `::-webkit-scrollbar`s (which make macOS scrollbars always visible).
 `@theme inline` maps tokens to Tailwind utilities (`bg-primary`,
 `text-icon-folder`, `bg-toolbar-2`, `bg-cursor-tint`). File-type icon colors
-come from Oxide's hue scales (800 steps dark, 600 light). **Interface scale** (`settings.uiScale`,
+come from Oxide's hue scales (800 steps dark, 600 light). **Icon sizes** follow
+TDesign's rule (an icon is 2px larger than its text, in whole pixels) through
+four rem tokens, and every `<ng-icon>` takes one: `--icon-size-sm` 14px (beside
+11–12px text, small icon buttons), `-md` 16px (13–14px text: file rows, window
+titles; the path-bar buttons), `-lg` 20px and `-xl` 24px (lone spinners and
+status marks). **Interface scale** (`settings.uiScale`,
 0.5–4 in 0.1 steps): one root font-size lever — `applyUiScale` sets
 `html { font-size: 16px * scale }`, and since EVERY size in the app is rem
 (panel tokens like `--row-h`, all Tailwind utilities, ng-icon sizes), the

docs/gotchas.md

@@ -76,6 +76,12 @@ touching the adjacent code.
   moment the pseudo-element is styled, WKWebView draws classic always-visible
   scrollbars that take layout width. Deliberate here (square design); don't
   reach for it to "tint" scrollbars without accepting that.
+- **An icon size is one of the four `--icon-size-*` tokens, never a one-off
+  rem.** TDesign glyphs are 24-unit SVGs with 2-unit strokes, so a fractional
+  size (0.9rem = 14.4px) lands every stroke between device pixels and blurs
+  it. Per-template picks had drifted to 12 sizes, and neighbours stopped
+  matching: a 14.4px cog beside a 12.8px +, and a 12px + beside 9.6px × in
+  the shortcut chips.
 
 ## The interface scale (root font-size lever)