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/view/bootstrap.rs

@@ -0,0 +1,134 @@
+#![allow(dead_code)] // Phase 2.5: consumed by render_screen dispatch
+
+//! Bootstrap screen view.
+//!
+//! Shown when the database has no entity data. Guides users to run
+//! a sync to populate the database.
+
+use ftui::core::geometry::Rect;
+use ftui::render::cell::{Cell, PackedRgba};
+use ftui::render::drawing::Draw;
+use ftui::render::frame::Frame;
+
+use crate::state::bootstrap::BootstrapState;
+
+// Colors (Flexoki palette).
+const TEXT: PackedRgba = PackedRgba::rgb(0xCE, 0xCD, 0xC3); // tx
+const MUTED: PackedRgba = PackedRgba::rgb(0x87, 0x87, 0x80); // tx-2
+const ACCENT: PackedRgba = PackedRgba::rgb(0xDA, 0x70, 0x2C); // orange
+
+/// Render the bootstrap screen.
+///
+/// Centers a message in the content area, guiding the user to start a sync.
+/// When a sync is in progress, shows a "syncing" message instead.
+pub fn render_bootstrap(frame: &mut Frame<'_>, state: &BootstrapState, area: Rect) {
+    if area.width < 10 || area.height < 5 {
+        return;
+    }
+
+    let center_y = area.y + area.height / 2;
+    let max_x = area.x.saturating_add(area.width);
+
+    // Title.
+    let title = "No data found";
+    let title_x = area.x + area.width.saturating_sub(title.len() as u16) / 2;
+    frame.print_text_clipped(
+        title_x,
+        center_y.saturating_sub(2),
+        title,
+        Cell {
+            fg: ACCENT,
+            ..Cell::default()
+        },
+        max_x,
+    );
+
+    if state.sync_started {
+        // Sync in progress.
+        let msg = "Syncing data from GitLab...";
+        let msg_x = area.x + area.width.saturating_sub(msg.len() as u16) / 2;
+        frame.print_text_clipped(
+            msg_x,
+            center_y,
+            msg,
+            Cell {
+                fg: TEXT,
+                ..Cell::default()
+            },
+            max_x,
+        );
+    } else {
+        // Prompt user to start sync.
+        let msg = "Run sync to get started.";
+        let msg_x = area.x + area.width.saturating_sub(msg.len() as u16) / 2;
+        frame.print_text_clipped(
+            msg_x,
+            center_y,
+            msg,
+            Cell {
+                fg: TEXT,
+                ..Cell::default()
+            },
+            max_x,
+        );
+
+        let hint = "Press 'g' then 's' to start sync, or 'q' to quit.";
+        let hint_x = area.x + area.width.saturating_sub(hint.len() as u16) / 2;
+        frame.print_text_clipped(
+            hint_x,
+            center_y + 2,
+            hint,
+            Cell {
+                fg: MUTED,
+                ..Cell::default()
+            },
+            max_x,
+        );
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ftui::render::grapheme_pool::GraphemePool;
+
+    macro_rules! with_frame {
+        ($width:expr, $height:expr, |$frame:ident| $body:block) => {{
+            let mut pool = GraphemePool::new();
+            let mut $frame = Frame::new($width, $height, &mut pool);
+            $body
+        }};
+    }
+
+    #[test]
+    fn test_render_bootstrap_no_panic() {
+        with_frame!(80, 24, |frame| {
+            let state = BootstrapState::default();
+            render_bootstrap(&mut frame, &state, Rect::new(0, 1, 80, 22));
+        });
+    }
+
+    #[test]
+    fn test_render_bootstrap_sync_started() {
+        with_frame!(80, 24, |frame| {
+            let state = BootstrapState {
+                sync_started: true,
+                ..Default::default()
+            };
+            render_bootstrap(&mut frame, &state, Rect::new(0, 1, 80, 22));
+        });
+    }
+
+    #[test]
+    fn test_render_bootstrap_tiny_area_noop() {
+        with_frame!(8, 3, |frame| {
+            let state = BootstrapState::default();
+            render_bootstrap(&mut frame, &state, Rect::new(0, 0, 8, 3));
+            // Should not panic — early return for tiny areas.
+        });
+    }
+}