fix(tui): align session picker scope

[kitlangton]

What

The session picker now derives its initial project scope from the Tabs > Scope setting. Global tabs start the picker in all projects; per-directory tabs start it in current directory.

A picker scope changed with ctrl+a remains persisted and continues to override the initial default on later opens.

Before / After

Before: A user with global tabs opened the session picker in current-directory mode until they manually toggled ctrl+a.

After: A fresh picker preference follows the configured tab scope, while an explicit picker toggle remains remembered.

How

packages/tui/src/component/dialog-session-list.tsx reads the resolved TUI config and seeds session-list.allProjects from whether tabs.scope is global.

Scope

This is stacked on #39783, which changes the tab-scope default itself. This PR only aligns the session picker’s initial scope; it does not remove the picker’s independent persisted override.

Testing

• bun typecheck from packages/tui
• Full workspace typecheck run by the pre-push hook
• bunx prettier --check src/component/dialog-session-list.tsx

Stack

1. fix(tui): default tabs to global scope #39783
2. fix(tui): align session picker scope #39784 👈 current