Make the composer wrap and grow, and surface Launch at Login

Long prompts hit a single-line field before; the composer is now an
NSTextView that wraps and grows up to seven lines, keeps Return as send,
and uses Shift+Return for a newline. Launch at Login already existed in
the menu bar icon's right-click menu, so it is now also a toggle in the
sync panel where it is easier to find.

AGENTS.md

@@ -13,7 +13,8 @@ clicking an item copies it back to the clipboard.
   `NSStatusItem Preferred Position Prompt`). Left click toggles the panel,
   right click shows the menu (accessibility state, launch at login, open data
   folder, quit). Contains the single-instance guard and `LoginItem`
-  (`SMAppService`). Also sets `NSApp.mainMenu` with Hide Panel (Cmd+W) and Quit
+  (`SMAppService`). The sync panel also carries a Launch at Login toggle (the
+  app's only settings surface). Also sets `NSApp.mainMenu` with Hide Panel (Cmd+W) and Quit
   (Cmd+Q) — an accessory app shows no menu bar, but the main menu still
   services key equivalents, which is the only way to quit from the keyboard
   while the panel has focus. `applicationShouldHandleReopen` shows the panel so
@@ -37,6 +38,13 @@ clicking an item copies it back to the clipboard.
   light mode keeps the system window colour. `Theme.background` is also handed
   to the `NSPanel` so the strip under the transparent titlebar matches, and the
   row colour stays slightly lighter than black so cards remain visible.
+- `Sources/Prompt/ComposerView.swift` — the chat-style composer
+  (`NSViewRepresentable` around an `NSTextView`): wraps long prompts, grows to
+  fit up to seven lines, then scrolls. Return submits, Shift+Return inserts a
+  newline, Esc forwards to the panel (clear selection, else hide). Height is
+  measured from the text and pushed into a `height` binding the panel applies
+  as a frame — a representable cannot resize itself through
+  `intrinsicContentSize` once SwiftUI offers a larger size.
 - `Sources/Prompt/PanelView.swift` — the panel UI. Header (workspace switcher,
   search, add photos), item list, composer. There is no in-header close button:
   the window's own close button hides the panel. Composer `# Name` creates/