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/crash_context.rs

@@ -168,6 +168,13 @@ impl CrashContext {
     ///
     /// Captures the current events via a snapshot. The hook chains with
     /// the default panic handler so backtraces are still printed.
+    ///
+    /// FIXME: This snapshots events at install time, which is typically
+    /// during init() when the buffer is empty. The crash dump will only
+    /// contain the panic itself, not the preceding key presses and state
+    /// transitions. Fix requires CrashContext to use interior mutability
+    /// (Arc<Mutex<VecDeque<CrashEvent>>>) so the panic hook reads live
+    /// state instead of a stale snapshot.
     pub fn install_panic_hook(ctx: &Self) {
         let snapshot: Vec<CrashEvent> = ctx.events.iter().cloned().collect();
         let prev_hook = std::panic::take_hook();