[codex] fix terminal Mac Option symbols

[jimmystridh]

Problem

On macOS, the embedded terminal did not allow keyboard-layout characters produced with the Option key. In practice this meant users could not type currency symbols such as Option+3 for $ or Option+4 for € in the terminal.

Root cause

The xterm instance was created with macOptionIsMeta: true. That makes xterm treat Option as Meta and convert Option-key input into escape/meta sequences instead of allowing macOS keyboard layouts to emit printable characters.

Fix

• Set macOptionIsMeta to false for new terminal instances so Option remains available for printable layout characters.
• Apply the same option when cached terminal instances are reattached, so existing xterm caches pick up the behavior.
• Keep Option+Left and Option+Right word navigation through the existing custom key handler.
• Add an e2e guard that asserts the terminal keeps macOS Option available for printable characters.

Validation

• pnpm --filter @slayzone/app build
• pnpm --filter @slayzone/terminal typecheck
• pnpm --filter @slayzone/app exec playwright test --config playwright.config.ts e2e/terminal/30-terminal-core-behavior.spec.ts -g "lets macOS Option"

[jimmystridh]

Superseded by #97. This first PR was opened from an existing local branch that contained unrelated older commits, so I replaced it with a clean branch based on main.