fix(coach): say when the attachment picker list is cut

The Coach's "Choose from documents" picker reads the newest fifty
documents and dropped the route's nextCursor, so with a longer vault an
older report seemed not to exist unless one already knew to search for
it. A cut list now ends with the same line the document picker shows:
how many are shown and that the search reaches the rest. The document
row moves into its own component, which takes AttachmentPicker under
the function-size cap.

src/__tests__/baselines/source-function-lines.json

@@ -1,7 +1,7 @@
 {
   "$comment": "Production functions over 200 lines, keyed \"file :: name\", and their length. Maintained by src/__tests__/source-size-ratchet.test.ts.",
-  "count": 338,
-  "total": 109885,
+  "count": 337,
+  "total": 109677,
   "entries": {
     "app/achievements/page.tsx :: AchievementsPage": 206,
     "app/api/admin/backups/upload/route.ts :: apiHandler(arg)": 275,
@@ -99,7 +99,6 @@
     "components/documents/sources/document-source-picker.tsx :: DocumentSourcePicker": 563,
     "components/illness/log-day-sheet.tsx :: LogDaySheet": 265,
     "components/illness/new-episode-sheet.tsx :: NewEpisodeSheet": 264,
-    "components/insights/coach-panel/attachment-picker.tsx :: AttachmentPicker": 208,
     "components/insights/coach-panel/chat-bubble.tsx :: ChatBubbleImpl": 419,
     "components/insights/coach-panel/coach-conversation.tsx :: CoachConversation": 1002,
     "components/insights/coach-panel/coach-input.tsx :: CoachInput": 259,