feat(tui): Phase 3 power features — Who, Search, Timeline, Trace, File History screens

Complete TUI Phase 3 implementation with all 5 power feature screens:

- Who screen: 5 modes (expert/workload/reviews/active/overlap) with
  mode tabs, input bar, result rendering, and hint bar
- Search screen: full-text search with result list and scoring display
- Timeline screen: chronological event feed with time-relative display
- Trace screen: file provenance chains with expand/collapse, rename
  tracking, and linked issues/discussions
- File History screen: per-file MR timeline with rename chain display
  and discussion snippets

Also includes:
- Command palette overlay (fuzzy search)
- Bootstrap screen (initial sync flow)
- Action layer split from monolithic action.rs to per-screen modules
- Entity and render cache infrastructure
- Shared who_types module in core crate
- All screens wired into view/mod.rs dispatch
- 597 tests passing, clippy clean (pedantic + nursery), fmt clean

crates/lore-tui/src/state/bootstrap.rs

@@ -0,0 +1,160 @@
+#![allow(dead_code)] // Phase 2.5: consumed by Bootstrap screen
+
+//! Bootstrap screen state.
+//!
+//! Handles first-launch and empty-database scenarios. The schema
+//! preflight runs before the TUI event loop; the bootstrap screen
+//! guides users to sync when no data is available.
+
+// ---------------------------------------------------------------------------
+// DataReadiness
+// ---------------------------------------------------------------------------
+
+/// Result of checking whether the database has enough data to show the TUI.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct DataReadiness {
+    /// Database has at least one issue.
+    pub has_issues: bool,
+    /// Database has at least one merge request.
+    pub has_mrs: bool,
+    /// Database has at least one search document.
+    pub has_documents: bool,
+    /// Current schema version from the schema_version table.
+    pub schema_version: i32,
+}
+
+impl DataReadiness {
+    /// Whether the database has any entity data at all.
+    #[must_use]
+    pub fn has_any_data(&self) -> bool {
+        self.has_issues || self.has_mrs
+    }
+}
+
+// ---------------------------------------------------------------------------
+// SchemaCheck
+// ---------------------------------------------------------------------------
+
+/// Result of schema version validation.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum SchemaCheck {
+    /// Schema is at or above the minimum required version.
+    Compatible { version: i32 },
+    /// No database or no schema_version table found.
+    NoDB,
+    /// Schema exists but is too old for this TUI version.
+    Incompatible { found: i32, minimum: i32 },
+}
+
+// ---------------------------------------------------------------------------
+// BootstrapState
+// ---------------------------------------------------------------------------
+
+/// State for the Bootstrap screen.
+#[derive(Debug, Default)]
+pub struct BootstrapState {
+    /// Whether a data readiness check has completed.
+    pub readiness: Option<DataReadiness>,
+    /// Whether the user has initiated a sync from the bootstrap screen.
+    pub sync_started: bool,
+}
+
+impl BootstrapState {
+    /// Apply a data readiness result.
+    pub fn apply_readiness(&mut self, readiness: DataReadiness) {
+        self.readiness = Some(readiness);
+    }
+
+    /// Whether we have data (and should auto-transition to Dashboard).
+    #[must_use]
+    pub fn should_transition_to_dashboard(&self) -> bool {
+        self.readiness
+            .as_ref()
+            .is_some_and(DataReadiness::has_any_data)
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_data_readiness_has_any_data() {
+        let empty = DataReadiness {
+            has_issues: false,
+            has_mrs: false,
+            has_documents: false,
+            schema_version: 26,
+        };
+        assert!(!empty.has_any_data());
+
+        let with_issues = DataReadiness {
+            has_issues: true,
+            ..empty.clone()
+        };
+        assert!(with_issues.has_any_data());
+
+        let with_mrs = DataReadiness {
+            has_mrs: true,
+            ..empty
+        };
+        assert!(with_mrs.has_any_data());
+    }
+
+    #[test]
+    fn test_schema_check_variants() {
+        let compat = SchemaCheck::Compatible { version: 26 };
+        assert!(matches!(compat, SchemaCheck::Compatible { version: 26 }));
+
+        let no_db = SchemaCheck::NoDB;
+        assert!(matches!(no_db, SchemaCheck::NoDB));
+
+        let incompat = SchemaCheck::Incompatible {
+            found: 10,
+            minimum: 20,
+        };
+        assert!(matches!(
+            incompat,
+            SchemaCheck::Incompatible {
+                found: 10,
+                minimum: 20
+            }
+        ));
+    }
+
+    #[test]
+    fn test_bootstrap_state_default() {
+        let state = BootstrapState::default();
+        assert!(state.readiness.is_none());
+        assert!(!state.sync_started);
+        assert!(!state.should_transition_to_dashboard());
+    }
+
+    #[test]
+    fn test_bootstrap_state_apply_readiness_empty() {
+        let mut state = BootstrapState::default();
+        state.apply_readiness(DataReadiness {
+            has_issues: false,
+            has_mrs: false,
+            has_documents: false,
+            schema_version: 26,
+        });
+        assert!(!state.should_transition_to_dashboard());
+    }
+
+    #[test]
+    fn test_bootstrap_state_apply_readiness_with_data() {
+        let mut state = BootstrapState::default();
+        state.apply_readiness(DataReadiness {
+            has_issues: true,
+            has_mrs: false,
+            has_documents: false,
+            schema_version: 26,
+        });
+        assert!(state.should_transition_to_dashboard());
+    }
+}