Unify attachment display and enable file uploads on all platforms (#1501)

Attachment pills were drawn by four separate style sets, so files,
images, GitHub items, and reviews rendered at different heights in the
same tray. Move the frame, the two-line label, and the image thumbnail
into shared components so every attachment lines up at one height,
across both the composer and sent messages.

Sent-message images now open the lightbox, and file uploads work on
iOS and Android via expo-document-picker instead of being gated to
desktop.

packages/app/src/i18n/resources/en.ts

@@ -108,7 +108,7 @@ export const en = {
       removeFile: "Remove file attachment",
       openGithub: "Open {{kind}} #{{number}}",
       removeGithub: "Remove {{kind}} #{{number}}",
-      browserElement: "Element · {{tag}}",
+      element: "Element",
       openBrowserElement: "Open browser element attachment",
       removeBrowserElement: "Remove browser element attachment",
       openReview: "Open review attachment",
@@ -254,9 +254,12 @@ export const en = {
       imageUnavailable: "Image unavailable",
       imagePreviewUnavailable: "Image preview unavailable.",
       imagePreviewLoadFailed: "Unable to load image preview.",
-      reviewOne: "Review · 1 comment",
-      reviewMany: "Review · {{count}} comments",
+      review: "Review",
+      commentsOne: "1 comment",
+      commentsMany: "{{count}} comments",
       textAttachment: "Text attachment",
+      text: "Text",
+      file: "File",
     },
     speak: {
       header: "Spoke",