Plan 04: Layout Shell

Summary

Replace fixed Hello World panels with the real native macOS layout shell: collapsible and resizeable sidebar, central workspace, right tool panel, selected-thread bottom terminal region, and a visible entry point for archived threads. This plan also owns persisting panel sizes and collapsed states (additive migration on top of Plan 02).

Requirements

• Technical Requirements: App Layout, Right Tool Panel, Global Navigation, Theme.
• Non-Functional Requirements: Responsiveness, Accessibility, Usability, Maintainability.
• Testing Requirements: E2E Scope, Screenshot Requirements.
• Standards: SwiftUI Standard, AppKit Standard.

Implementation

• Implement the main app layout with native macOS split behavior where SwiftUI is sufficient.
• Use AppKit behind a narrow bridge only where SwiftUI does not provide acceptable resize/collapse behavior.
• Add a collapsible sidebar, collapsible right tool panel, and collapsed-by-default selected-thread bottom terminal.
• Sidebar MUST include a visible archive entry point (e.g. an “Archived” disclosure section or a dedicated row) so threads archived in Plan 03 remain reachable. Archived threads stay grouped under their project.
• Add a SQLite migration (version 3) for panel sizes and collapsed states: sidebar width, right-panel width, bottom-terminal height when expanded, sidebar collapsed flag, right-panel collapsed flag, bottom-terminal expanded flag.
• Persist layout state through that migration. Loading layout state MUST tolerate missing rows so a fresh database falls back to documented defaults.
• Keep terminal contents placeholder-backed in this plan.
• Apply Dracula tokens consistently to the layout shell, selection states, and resize handles.

Tests

• Unit tests for layout state persistence against a real temporary SQLite file, including the missing-row default behavior.
• Unit tests for archive section visibility given an empty archive vs. a populated archive.
• UI-level or integration tests for collapse/expand action state.
• Screenshot-capable smoke coverage once the E2E harness exists (Plan 10).

Acceptance Criteria

• Sidebar, main workspace, right panel, and selected-thread bottom terminal regions are visible in the app shell.
• Sidebar and right panel can collapse and expand.
• Selected-thread bottom terminal starts collapsed and toggles with Cmd+J.
• Archived threads remain reachable through a visible sidebar entry point.
• Major panel sizes and collapsed states persist across app relaunch via the new migration.
• Layout state remains independent from terminal implementation.
• scripts/build.sh passes.
• scripts/test.sh passes with layout-state coverage.