feat(claudbg-ysj0): prevent transcript overflow and add Ctrl+L redraw

Switch chat-log layout constraint from Min(0) to Fill(1) to ensure the
transcript panel never bleeds into the sub-agents panel. Add Ctrl+L
keybinding (global + transcript screen) that sets needs_clear, causing
terminal.clear() before the next draw to flush rendering artifacts. Update
help modal to document Ctrl+L.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.beans/claudbg-ysj0--tui-prevent-transcript-overflow-into-sub-agents-pa.md

@@ -1,10 +1,11 @@
 ---
 # claudbg-ysj0
 title: 'TUI: prevent transcript overflow into sub-agents panel; add Ctrl+L to redraw'
-status: todo
+status: in-progress
 type: bug
+priority: normal
 created_at: 2026-04-01T16:47:10Z
-updated_at: 2026-04-01T16:47:10Z
+updated_at: 2026-04-01T16:51:47Z
 ---
 
 Occasionally the Transcript widget overflows into the Sub-Agents panel, making the UI look broken. Prevent this overflow from happening. Also add a Ctrl+L keybinding to force a full screen redraw/reset to recover from any rendering artifacts.

src/tui/modals/help_modal.rs

@@ -16,7 +16,7 @@ use crate::tui::state::AppState;
 
 /// Dialog dimensions.
 const DIALOG_WIDTH: u16 = 36;
-const DIALOG_HEIGHT: u16 = 36;
+const DIALOG_HEIGHT: u16 = 37;
 
 /// Compute a centered [`Rect`] of the given size within `area`.
 fn centered_rect(width: u16, height: u16, area: Rect) -> Rect {
@@ -71,7 +71,8 @@ const HELP_TEXT: &str = "\
  Global\n\
   q/Q       quit\n\
   ?         this help\n\
-  c         toggle color";
+  c         toggle color\n\
+  Ctrl+L    redraw screen";
 
 // ---------------------------------------------------------------------------
 // Rendering

src/tui/run.rs

@@ -15,7 +15,7 @@ use std::time::Duration;
 
 use ratatui::Terminal;
 use ratatui::backend::CrosstermBackend;
-use ratatui::crossterm::event::{self, Event, KeyCode, KeyEventKind};
+use ratatui::crossterm::event::{self, Event, KeyCode, KeyEventKind, KeyModifiers};
 use ratatui::crossterm::execute;
 use ratatui::crossterm::terminal::{
     EnterAlternateScreen, LeaveAlternateScreen, disable_raw_mode, enable_raw_mode,
@@ -145,6 +145,11 @@ fn handle_event(event: Event, state: &mut AppState) {
         if key.kind != KeyEventKind::Press {
             return;
         }
+        // Ctrl+L: force a full terminal redraw to clear any rendering artifacts.
+        if key.code == KeyCode::Char('l') && key.modifiers.contains(KeyModifiers::CONTROL) {
+            state.needs_clear = true;
+            return;
+        }
         match key.code {
             KeyCode::Char('q') => state.should_quit = true,
             KeyCode::Char('c') => state.color_enabled = !state.color_enabled,
@@ -297,6 +302,12 @@ pub fn run_tui() -> Result<()> {
         // Load transcript data lazily when entering a transcript screen.
         maybe_load_transcript(&mut state);
 
+        // Ctrl+L: clear all terminal cells before the next draw to remove artifacts.
+        if state.needs_clear {
+            guard.terminal.clear()?;
+            state.needs_clear = false;
+        }
+
         // Record the visible chat-log height before rendering so that
         // Space / PageDown / PageUp can scroll by exactly one page.
         // Layout: 4-row stats header + 3-row search bar + 2 border rows = 9 fixed rows.

src/tui/screens/transcript.rs

@@ -432,9 +432,13 @@ pub fn render_transcript(f: &mut Frame, area: Rect, state: &AppState) {
     f.render_widget(header_paragraph, chunks[0]);
 
     // ── Chat log + sub-agents panel (horizontal split) ──────────────────────
+    // Use Fill(1) + Length(30) so the chat log gets all remaining space after
+    // the sub-agents panel is allocated its fixed 30 columns.  Fill is
+    // preferred over Min(0) here because it avoids any layout solver edge
+    // cases where Min(0) could allow content to escape its allocated rect.
     let body_chunks = Layout::default()
         .direction(Direction::Horizontal)
-        .constraints([Constraint::Min(0), Constraint::Length(30)])
+        .constraints([Constraint::Fill(1), Constraint::Length(30)])
         .split(chunks[1]);
 
     // ── Chat log ─────────────────────────────────────────────────────────────
@@ -551,6 +555,11 @@ pub fn handle_transcript_event(event: Event, state: &mut AppState) -> bool {
         state.pending_g = false;
     }
 
+    // Ctrl+L: request a full terminal redraw; pass through to global handler.
+    if key.code == KeyCode::Char('l') && key.modifiers.contains(KeyModifiers::CONTROL) {
+        return false;
+    }
+
     match key.code {
         // Toggle focus: ChatLog → SubagentsPanel → SearchInput → ChatLog.
         KeyCode::Tab => {

src/tui/state.rs

@@ -179,6 +179,11 @@ pub struct AppState {
     // ── Lifecycle ───────────────────────────────────────────────────────────
     /// Set to `true` to signal the event loop to exit.
     pub should_quit: bool,
+    /// Set to `true` to request a full terminal clear before the next draw.
+    ///
+    /// Cleared automatically by the event loop after `terminal.clear()` is called.
+    /// Used by Ctrl+L to recover from rendering artifacts.
+    pub needs_clear: bool,
 }
 
 impl AppState {
@@ -258,6 +263,7 @@ impl AppState {
             pending_g: false,
             color_enabled,
             should_quit: false,
+            needs_clear: false,
         }
     }