feat: add TUI prompt history recall

[sam-saffron-jarvis]

What

Adds shell-style Up/Down prompt history recall in the TUI composer.

• Uses persisted messages rows as shared cross-session prompt history
• Traverses global user prompts by monotonic messages.id, filtered to the current agent
• Preserves the local unsent draft while browsing history and restores it when moving down past newest
• Lets Up/Down move within multiline composer text before falling back to history
• Works in the streaming interjection composer before viewport arrow scrolling takes over
• Keeps recalled history text-only so stale draft files/images are not accidentally sent

Why

This matches the expected terminal behavior:

1. terminal 1 sends a prompt
2. terminal 2 sends a prompt in another session
3. terminal 1 types a draft and presses Up
4. terminal 1 recalls terminal 2's newer persisted prompt, and Down restores the draft

Verification

• go test ./...
• go build ./...
• go vet ./...