Complete Phase 1: parallel sync, IPC, theme colors, lazy CLI loading

- Sync: Parallelize message downloads with asyncio.gather (batch size 5)
- Sync: Increase HTTP semaphore from 2 to 5 concurrent requests
- Sync: Add IPC notifications to sync daemon after sync completes
- Mail: Replace all hardcoded RGB colors with theme variables
- Mail: Remove envelope icon/checkbox gap (padding cleanup)
- Mail: Add IPC listener for refresh notifications from sync
- Calendar: Style current time line with error color and solid line
- Tasks: Fix table not displaying (CSS grid to horizontal layout)
- CLI: Implement lazy command loading for faster startup (~12s to ~0.3s)
- Add PROJECT_PLAN.md with full improvement roadmap
- Add src/utils/ipc.py for Unix socket cross-app communication

src/tasks/app.py

@@ -46,24 +46,20 @@ class TasksApp(App):
 
     CSS = """
     Screen {
-        layout: grid;
-        grid-size: 2;
-        grid-columns: auto 1fr;
-        grid-rows: auto 1fr auto auto;
+        layout: horizontal;
     }
 
     Header {
-        column-span: 2;
+        dock: top;
     }
 
     Footer {
-        column-span: 2;
+        dock: bottom;
     }
 
     #sidebar {
         width: 28;
         height: 100%;
-        row-span: 1;
     }
 
     #sidebar.hidden {
@@ -116,7 +112,6 @@ class TasksApp(App):
         background: $surface;
         color: $text-muted;
         padding: 0 1;
-        column-span: 2;
     }
 
     #detail-pane {
@@ -124,7 +119,6 @@ class TasksApp(App):
         height: 50%;
         border-top: solid $primary;
         background: $surface;
-        column-span: 2;
     }
 
     #detail-pane.hidden {
@@ -154,7 +148,6 @@ class TasksApp(App):
         border-top: solid $primary;
         padding: 1;
         background: $surface;
-        column-span: 2;
     }
 
     #notes-pane.hidden {