docs: tighten the comments and skill text around multi-line input

- sendInput's docstring said all text without `\r` is typed; that now holds
  for single-line text only.
- The skill's big-input section still listed "the newline stripping" among
  the hazards a workspace file avoids; it is the unconfirmed multi-line
  paste now. Rewrapped, mirrored in plugins/codeman.
- The mobile composer's hand-back comment said the prompt transport strips
  newlines. The hand-back writes to the terminal prompt, whose text reaches
  the PTY as typed input, where a newline is a key; the behaviour (a
  multi-line draft stays parked) is unchanged.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/web/public/keyboard-accessory.js

@@ -1415,9 +1415,10 @@ const KeyboardAccessoryBar = {
     overlay.querySelector('.prompt-composer-terminal').addEventListener('click', () => {
       // Hand the text BACK to the terminal prompt so both surfaces hold the same
       // prompt, the mirror of the adoption composePrompt() does on open. Only a
-      // single-line draft can make the trip: the prompt transport is single-line
-      // and strips embedded newlines, so a multi-line draft would arrive mangled
-      // and instead stays parked as a draft (the dot on the Compose key shows it).
+      // single-line draft can make the trip: the terminal prompt is one line and
+      // its text reaches the PTY as typed input, where an embedded newline is a
+      // key, so a multi-line draft would arrive mangled and instead stays parked
+      // as a draft (the dot on the Compose key shows it).
       const text = textarea.value;
       if (!text || text.includes('\n')) {
         close({ focusTerminal: true });