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/app/mod.rs

@@ -0,0 +1,73 @@
+#![allow(dead_code)] // Phase 1: methods consumed as screens are implemented
+
+//! Full FrankenTUI Model implementation for the lore TUI.
+//!
+//! LoreApp is the central coordinator: it owns all state, dispatches
+//! messages through a 5-stage key pipeline, records crash context
+//! breadcrumbs, manages async tasks via the supervisor, and routes
+//! view() to per-screen render functions.
+
+mod tests;
+mod update;
+
+use crate::clock::{Clock, SystemClock};
+use crate::commands::{CommandRegistry, build_registry};
+use crate::crash_context::CrashContext;
+use crate::db::DbManager;
+use crate::message::InputMode;
+use crate::navigation::NavigationStack;
+use crate::state::AppState;
+use crate::task_supervisor::TaskSupervisor;
+
+// ---------------------------------------------------------------------------
+// LoreApp
+// ---------------------------------------------------------------------------
+
+/// Root model for the lore TUI.
+///
+/// Owns all state and implements the FrankenTUI Model trait. The
+/// update() method is the single entry point for all state transitions.
+pub struct LoreApp {
+    pub state: AppState,
+    pub navigation: NavigationStack,
+    pub supervisor: TaskSupervisor,
+    pub crash_context: CrashContext,
+    pub command_registry: CommandRegistry,
+    pub input_mode: InputMode,
+    pub clock: Box<dyn Clock>,
+    pub db: Option<DbManager>,
+}
+
+impl LoreApp {
+    /// Create a new LoreApp with default state.
+    ///
+    /// Uses a real system clock and no DB connection (set separately).
+    #[must_use]
+    pub fn new() -> Self {
+        Self {
+            state: AppState::default(),
+            navigation: NavigationStack::new(),
+            supervisor: TaskSupervisor::new(),
+            crash_context: CrashContext::new(),
+            command_registry: build_registry(),
+            input_mode: InputMode::Normal,
+            clock: Box::new(SystemClock),
+            db: None,
+        }
+    }
+
+    /// Create a LoreApp for testing with a custom clock.
+    #[cfg(test)]
+    fn with_clock(clock: Box<dyn Clock>) -> Self {
+        Self {
+            clock,
+            ..Self::new()
+        }
+    }
+}
+
+impl Default for LoreApp {
+    fn default() -> Self {
+        Self::new()
+    }
+}