feat(export-ui): Display 드롭다운/테마컬러 HEX 검증 반영(TDD)

components/BuilderClientPage.tsx

@@ -223,7 +223,13 @@ export default function BuilderClientPage() {
     if (manifestShortName && manifestShortName.trim().length > 0) manifestOverrideBase.short_name = manifestShortName.trim()
     if (manifestStartUrl && manifestStartUrl.trim().length > 0) manifestOverrideBase.start_url = manifestStartUrl.trim()
     if (manifestDisplay && manifestDisplay.trim().length > 0) manifestOverrideBase.display = manifestDisplay.trim()
-    if (manifestThemeColor && manifestThemeColor.trim().length > 0) manifestOverrideBase.theme_color = manifestThemeColor.trim()
+    if (manifestThemeColor && manifestThemeColor.trim().length > 0) {
+      const v = manifestThemeColor.trim()
+      const hexOk = /^#([0-9a-fA-F]{3}){1,2}$/.test(v)
+      if (hexOk) {
+        manifestOverrideBase.theme_color = v
+      }
+    }
     const manifestOverride = Object.keys(manifestOverrideBase).length > 0 ? (manifestOverrideBase as { name?: string; short_name?: string; start_url?: string; display?: string; theme_color?: string }) : undefined
     const robotsTextOverride = (() => {
       const lines = (robotsDisallow || '').split(/\n+/).map((s) => s.trim()).filter((s) => s.length > 0)
@@ -334,14 +340,18 @@ export default function BuilderClientPage() {
               </label>
               <label className="block" htmlFor="ins-manifest-display">
                 <span className="sr-only">Manifest Display</span>
-                <input
+                <select
                   id="ins-manifest-display"
                   aria-label="Manifest Display"
                   className="border rounded px-3 py-2 w-full"
                   value={manifestDisplay}
                   onChange={(e) => setManifestDisplay(e.target.value)}
-                  placeholder="standalone"
-                />
+                >
+                  <option value="">(default)</option>
+                  <option value="standalone">standalone</option>
+                  <option value="minimal-ui">minimal-ui</option>
+                  <option value="browser">browser</option>
+                </select>
               </label>
               <label className="block" htmlFor="ins-manifest-theme-color">
                 <span className="sr-only">Manifest Theme Color</span>