fix(tds): resolve send-status and read-receipt colors from --lt-* vars

DP14: Message send-status icon and ReadReceiptAvatars pill hardcoded
dark-theme accent hex/rgba, so TDS light mode kept bright cyan/red
instead of the theme-overridden darker values. Route all colors/glows
through the theme-aware --lt-* CSS variables (mirroring EventReaders),
using color-mix for translucent tints and accent-alpha icon colors.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/components/read-receipt-avatars/ReadReceiptAvatars.tsx

@@ -106,12 +106,12 @@ export function ReadReceiptAvatars({
             display: 'flex',
             alignItems: 'center',
             backgroundColor: lotusTerminal
-              ? 'rgba(0,212,255,0.07)'
+              ? 'color-mix(in srgb, var(--lt-accent-cyan) 7%, transparent)'
               : color.SurfaceVariant.Container,
             border: lotusTerminal
-              ? `${config.borderWidth.B300} solid rgba(0,212,255,0.30)`
+              ? `${config.borderWidth.B300} solid color-mix(in srgb, var(--lt-accent-cyan) 30%, transparent)`
               : `${config.borderWidth.B300} solid transparent`,
-            boxShadow: lotusTerminal ? '0 0 10px rgba(0,212,255,0.12)' : 'none',
+            boxShadow: lotusTerminal ? 'var(--lt-box-glow-cyan)' : 'none',
             borderRadius: config.radii.Pill,
             padding: `${config.space.S100} ${config.space.S200}`,
             gap: '0px',