Select items by clicking the card instead of copying them

Copying was a side effect of a click, which made it impossible to build
a selection with the mouse and surprising when the intent was to pick
something up rather than copy it immediately. A click now selects (or
deselects), and copying is an explicit action from the selection bar or
the right-click menu.

README.md

@@ -2,25 +2,22 @@
 
 A native macOS app for keeping prompts and photos, in the spirit of
 [Copper](https://shadcn.com/copper) by shadcn: a floating panel that sits next
-to your work. Click anything to copy it back to your clipboard.
+to your work. Select what you need and send it back to your clipboard.
 
-- **Checkbox to select** — every item has a checkbox; tick several and act on
-  them at once (copy, delete, move, merge). Clicking the row itself still
-  copies that item.
-- **Click to copy** — text notes go back as text, photos go back as images.
+- **Click to select** — clicking a card selects it (Shift+click for a range),
+  and the selection bar copies a single item as-is, or the whole selection as a
+  numbered list or as plain newline-separated lines.
+- **Text or photo** — copying sends text back as text and a photo back as an
+  image.
 - **Capture from anywhere** — select text in any app and tap **Left Shift twice**.
 - **Photos** — paste (Cmd+V), drag & drop, or add via the photo button.
 - **Workspaces** — type `# Name` in the composer, or use "New Workspace" in
   the Cmd+K switcher (which opens a name modal); Cmd+K switches, and the
   up/down arrows in the switcher reorder them. (The code and the saved JSON
   still call these `sections` so existing data keeps working.)
-- **Copy as List / Copy as Lines** — select with the checkboxes (or Cmd+click,
-  or Shift+click for a range), then copy the selection as a numbered list or as
-  plain newline-separated text, from the selection bar, the right-click menu, or
-  Shift+Cmd+C / Option+Cmd+C. The same menu deletes, moves or merges the
-  selection.
-- **Merge Notes, Mark as Done, Edit, Move To** — right-click any item.
-- **Search** — Cmd+F searches across all sections.
+- **Right-click for actions** — Copy, Copy as List, Copy as Lines, Mark as Done,
+  Edit, Open, Merge Notes, Move To, Delete — each acting on the whole selection.
+- **Search** — Cmd+F searches across all workspaces.
 - **Sync (optional)** — generate an 8-digit code (`1234-5678`) on one Mac and
   enter it on the other; no account, no login. The code is the only secret.
 - **Local & private** — everything lives in