feat(tui): Phase 2 Issue List + MR List screens

Implement state, action, and view layers for both list screens:
- Issue List: keyset pagination, snapshot fence, filter DSL, label aggregation
- MR List: mirrors Issue pattern with draft/reviewer/target branch filters
- Migration 027: covering indexes for TUI list screen queries
- Updated Msg types to use typed Page structs instead of raw Vec<Row>
- 303 tests passing, clippy clean

Beads: bd-3ei1, bd-2kr0, bd-3pm2

crates/lore-tui/src/lib.rs

@@ -21,11 +21,16 @@ pub mod app; // LoreApp Model trait impl (Phase 0 proof: bd-2emv, full: bd-6pmy)
 // Phase 1 modules.
 pub mod commands; // CommandRegistry: keybindings, help, palette (bd-38lb)
 pub mod crash_context; // CrashContext ring buffer + panic hook (bd-2fr7)
+pub mod layout; // Responsive layout: breakpoints, columns, preview pane (bd-1pzj)
 pub mod navigation; // NavigationStack: back/forward/jump list (bd-1qpp)
 pub mod state; // AppState, LoadState, ScreenIntent, per-screen states (bd-1v9m)
 pub mod task_supervisor; // TaskSupervisor: dedup + cancel + generation IDs (bd-3le2)
 pub mod view; // View layer: render_screen + common widgets (bd-26f2)
 
+// Phase 2 modules.
+pub mod action; // Data-fetching actions for TUI screens (bd-35g5+)
+pub mod filter_dsl; // Filter DSL tokenizer for list screen filter bars (bd-18qs)
+
 /// Options controlling how the TUI launches.
 #[derive(Debug, Clone)]
 pub struct LaunchOptions {