fix(appearance): make match-terminal sidebar text inherit the terminal foreground (#29157)

Match Terminal only redefined --foreground on the sidebar surfaces, but
inherited text color comes from body's already-computed color, so labels
without their own color class (e.g. project names) stayed the app
foreground. Set color directly on the surface as well.

Fixes #29151

Co-authored-by: Neil <neil@stably.ai>

src/renderer/src/components/sidebar/Sidebar.test.tsx

@@ -166,9 +166,11 @@ describe('Sidebar', () => {
     })
 
     const markup = renderSidebar()
+    const sidebarRootTag = markup.slice(0, markup.indexOf('>'))
 
-    expect(markup).toContain('--worktree-sidebar:#101820')
-    expect(markup).toContain('--worktree-sidebar-foreground:#f0f4f8')
+    expect(sidebarRootTag).toContain('--worktree-sidebar:#101820')
+    expect(sidebarRootTag).toContain('--worktree-sidebar-foreground:#f0f4f8')
+    expect(sidebarRootTag).toMatch(/[;"]color:#f0f4f8/)
     expect(markup).toContain('data-testid="workspace-kanban-drawer"')
     expect(markup.match(/--worktree-sidebar:#101820/g)).toHaveLength(2)
   })

src/renderer/src/lib/left-sidebar-appearance.ts

@@ -74,6 +74,7 @@ function buildSurfaceVariables(args: {
   if (overrideTextTokens) {
     vars['--background'] = background
     vars['--foreground'] = foreground
+    vars.color = foreground
     vars['--card'] = `color-mix(in srgb, ${foreground} 4%, ${background})`
     vars['--card-foreground'] = foreground
     vars['--accent'] = `color-mix(in srgb, ${foreground} 9%, ${background})`