feat: add prompt composer to terminal context menu

[mpmisha]

What

Adds a notepad-style Prompt Composer to each AI-session terminal pane, accessible from the pane right-click context menu (📝 Prompt composer), the Command Palette, or the Ctrl+Alt+P (⌘⌥P on Mac) shortcut. Closes TASK-180.

Availability: The composer is intentionally surfaced only on AI-session panes (Copilot CLI, Claude Code, etc.) — same gating as Show prompts and Session summary. On a plain shell pane the context-menu item, the Command Palette entry, and the shortcut are all hidden / no-op.

Why

Composing long, multi-line prompts directly in the terminal is awkward — newlines and paste are fiddly, and a stray Enter submits a half-written message. The composer is a plain modal <textarea> so users can write and edit freely, then copy or paste the whole thing into the terminal as a single block.

How it works

Three buttons in the footer:

• 📋 Copy — write the draft to the clipboard, with transient "✓ Copied" feedback.
• ➤ Submit — bracketed-paste the draft into the focused terminal via writePty. We do not also send Enter — the user reviews in the terminal and presses Enter themselves. Intentional:
  • avoids accidental submission of half-thought-out prompts
  • Ink-based AI CLIs (Copilot CLI, Claude Code) handle a programmatic \r after bracketed paste inconsistently
• Close — dismiss (also bound to Esc and backdrop click).

Drafts persist per-terminal for the current session, so closing and reopening the dialog doesn't lose work. Drafts are dropped when the owning pane is closed, and the composer auto-dismisses if its target pane goes away.

Submit reuses the existing prepareClipboardPaste helper for bracketed-paste wrapping + CRLF→LF normalization (so Windows-CRLF drafts work cleanly).

Keyboard shortcut

Ctrl+Alt+P (rendered as ⌘⌥P on Mac) opens the composer for the focused pane. While adding this, the keybinding matcher was fixed to fall back to event.code on macOS — Option+letter on Mac produces special characters (Option+P → π), which broke matching against the literal p key. The fix also unblocks the pre-existing Ctrl+Alt+R and Ctrl+Alt+N bindings on Mac.

Files

Added

• src/renderer/components/PromptComposer.tsx — the modal
• src/renderer/utils/prompt-composer.ts — pure draft-map helpers (DRY + testable)
• tests/e2e/task-180-prompt-composer.spec.ts — 14 pure-function tests
• backlog/tasks/task-180 - …md — Backlog task

Modified

• src/renderer/state/terminal-store.ts — new state (promptComposerRequest, composerDrafts), open/close/setDraft actions, closeTerminal cleanup
• src/renderer/components/TerminalPanel.tsx — context menu item (AI-only) between "Show prompts" and "Session summary"
• src/renderer/components/CommandPalette.tsx — "Open Prompt Composer" entry (AI-only)
• src/renderer/components/ShortcutsHelp.tsx — Ctrl+Alt+P listed under the AI category
• src/renderer/hooks/useKeybindings.ts — Ctrl+Alt+P binding + event.code fallback for macOS Option-key combos
• src/renderer/App.tsx — mounts <PromptComposer />
• src/renderer/styles/global.css — .prompt-composer-* styles, matches the SessionSummary card family

Out of scope

• Persisting drafts across app restarts (session-only by design).
• Auto-pressing Enter after Submit (tried it, behaved inconsistently with AI CLIs; deferred).

Validation

• npx tsc --noEmit: no new errors introduced (same 32 pre-existing errors on this branch vs. main; remaining errors are all in unrelated code paths).
• npx vite build --config vite.renderer.config.ts: succeeds.
• npx playwright test tests/e2e/task-180-prompt-composer.spec.ts: 14/14 pass.
• Existing related specs (paste-wrap, smart-unwrap-on-copy) still pass.
• Manually smoke-tested in npm start: right-click AI pane → composer opens → Copy & Submit both work → Esc/backdrop close → draft persists across reopen → draft cleared on pane close → shortcut and Command Palette entry both hidden / no-op on plain shell panes.

assistance: agentic-cli
type: feature
agent-tool: copilot-cli
agent-model: claude-opus-4.7
work-item: TASK-180