[no bump] Implement telegra.ph media forward

Adds a share action to the Instant View photo viewer that downloads the
media and re-sends it from the user's own account with a text_url caption
linking back to the source article.

- src/main.py: hooks PhotoViewer.onPhotoShow, injects the toolbar item
- src/ivmedia.py: resolves the viewer's page block to a TL media object
- src/picker.py: share sheet + comment field (restores focus after the
  keyboard animation, which PhotoViewer.showShareAlert does itself)
- src/sender.py: FileLoader download, cache reuse, re-send with caption
- src/icons.py: IconManager-aware drawable lookup so icon packs apply
- tools/verify_bundle.py: offline checks for URL acceptance, caption
  entity shape and bundled-module isolation

Drops the sample greeting/textutil modules.

plugin.json

@@ -1,8 +1,8 @@
 {
-  "id": "hello_bundle",
-  "name": "Hello Bundle",
-  "description": "Multi-file exteraGram plugin built by tools/bundle.py",
-  "author": "@yourhandle",
+  "id": "telegraph_media_forward",
+  "name": "Telegraph Media Forward",
+  "description": "Adds a Forward action to media opened from telegra.ph pages: downloads the media and re-sends it from your account with a link back to the article.",
+  "author": "@lyuksovannyy",
   "version": "1.0.0",
   "icon": "exteraPlugins/1",
   "app_version": ">=12.5.1",