feat(learn): + opens a sheet as Claude's, Camera, Photos and Files, and what goes along in rounded rows

Following the developer's review of 3 Nov 2026 (ADR 0021, D67):

- + below the assistant's field, and below a conversation's follow-up,
  opens "Add to your question" as Claude's "Add to session": three big
  tiles side by side, Camera (where the device takes photos) and Photos
  for an assistant reading images, and Files; below them, in the field, a
  row leading to what goes along, showing how far the assistant looks and
  how many parts are chosen.
- Camera and Photos through image_picker (flutter.dev's own): the camera's
  own app and the system's photo picker, no permission asked on Android, a
  file dialog on the desktop, which has no Camera; photos made at most
  2048 pixels a side, read on the device like any file attached.
- What goes along is chosen in rounded rows, as Claude's Permission, in
  place of radio buttons and chips: how far it looks with a tick, private
  studysets with a switch, the parts each with a tick, a card's image with
  its thumbnail.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

pubspec.lock

@@ -737,6 +737,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.7.4"
+  flutter_plugin_android_lifecycle:
+    dependency: transitive
+    description:
+      name: flutter_plugin_android_lifecycle
+      sha256: "3854fe5e3bff0b113c658f260b90c95dea17c92db0f2addeac2e343dd9969785"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.35"
   flutter_secure_storage:
     dependency: transitive
     description:
@@ -1000,6 +1008,70 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.10.1"
+  image_picker:
+    dependency: transitive
+    description:
+      name: image_picker
+      sha256: e71b1bd9e40124041128d60fc3034c7b1598e1bba4e570bba0c70301c817013a
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.4"
+  image_picker_android:
+    dependency: transitive
+    description:
+      name: image_picker_android
+      sha256: "8a7823d5d3e884f7780829d85d92110d072bdcd9ed48e2be158d2abe91a912d4"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.8.13+25"
+  image_picker_for_web:
+    dependency: transitive
+    description:
+      name: image_picker_for_web
+      sha256: "66257a3191ab360d23a55c8241c91a6e329d31e94efa7be9cf7a212e65850214"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.1"
+  image_picker_ios:
+    dependency: transitive
+    description:
+      name: image_picker_ios
+      sha256: b8f508306db2bf71141aba2de4ec13456338bf01e13f034bd2594f341a5f8eb2
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.8.13+14"
+  image_picker_linux:
+    dependency: transitive
+    description:
+      name: image_picker_linux
+      sha256: "1f81c5f2046b9ab724f85523e4af65be1d47b038160a8c8deed909762c308ed4"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.2"
+  image_picker_macos:
+    dependency: transitive
+    description:
+      name: image_picker_macos
+      sha256: "86f0f15a309de7e1a552c12df9ce5b59fe927e71385329355aec4776c6a8ec91"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.2+1"
+  image_picker_platform_interface:
+    dependency: transitive
+    description:
+      name: image_picker_platform_interface
+      sha256: "2dee4b4e3be429db71472c9c559c981498070a61af1ba82e0e4986fc5dadc042"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.11.2"
+  image_picker_windows:
+    dependency: transitive
+    description:
+      name: image_picker_windows
+      sha256: d248c86554a72b5495a31c56f060cf73a41c7ff541689327b1a7dbccc33adfae
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.2"
   integration_test:
     dependency: transitive
     description: flutter