fix(mobile): chips read at 5:1 instead of 4.5:1

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: flamboh

apps/mobile/src/lib/composerChipPresentation.test.ts

@@ -70,7 +70,7 @@ const BUILT_IN_THEMES = MOBILE_THEME_IDS.filter((id) => id !== "material-you").f
 );
 
 describe("contextChipAccent", () => {
-  it("draws one color per theme that reads at 4.5:1 in messages, replies and the composer", () => {
+  it("draws one color per theme that reads at 5:1 in messages, replies and the composer", () => {
     for (const { name, theme } of BUILT_IN_THEMES) {
       for (const accent of CHIP_ACCENTS) {
         const shown = contextChipAccent(accent, theme, theme["--color-md-body"])!;
@@ -79,7 +79,7 @@ describe("contextChipAccent", () => {
           expect(
             contrastRatio(shown, surface),
             `${name}: ${accent} → ${shown} on ${surface}`,
-          ).toBeGreaterThanOrEqual(4.5);
+          ).toBeGreaterThanOrEqual(5);
         }
       }
     }
@@ -97,7 +97,7 @@ describe("contextChipAccent", () => {
         expect(
           contrastRatio(shown, surface),
           `${accent} → ${shown} on ${surface}`,
-        ).toBeGreaterThanOrEqual(4.5);
+        ).toBeGreaterThanOrEqual(5);
       }
     }
   });

apps/mobile/src/lib/composerChipPresentation.ts

@@ -45,6 +45,8 @@ const CONTEXT_CHIP_PRESENTATIONS = {
   },
 } as const satisfies Record<string, ContextChipPresentation>;
 
+const CHIP_CONTRAST = 5;
+
 const readableChipAccents = new Map<string, string>();
 
 /**
@@ -73,7 +75,7 @@ export function contextChipAccent(
   const key = [accent, ...surfaces].join();
   let readable = readableChipAccents.get(key);
   if (readable === undefined) {
-    readable = themeAccentWithContrast(accent, surfaces);
+    readable = themeAccentWithContrast(accent, surfaces, CHIP_CONTRAST);
     readableChipAccents.set(key, readable);
   }
   return readable;