feat(tui): responsive breakpoints for detail views (bd-a6yb)

Apply breakpoint-aware layout to issue_detail and mr_detail views:
- Issue detail: hide labels on Xs, hide assignees on Xs/Sm, skip milestone row on Xs
- MR detail: hide branch names and merge status on Xs/Sm
- Issue detail allocate_sections gives description 60% on wide (Lg+) vs 40% narrow
- Add responsive tests for both detail views
- Close bd-a6yb: all TUI screens now adapt to terminal width

760 lib tests pass, clippy clean.

crates/lore-tui/src/view/file_history.rs

@@ -17,22 +17,21 @@
 //! +-----------------------------------+
 //! ```
 
+use ftui::layout::Breakpoint;
 use ftui::render::cell::{Cell, PackedRgba};
 use ftui::render::drawing::Draw;
 use ftui::render::frame::Frame;
 
 use super::common::truncate_str;
+use super::{ACCENT, BG_SURFACE, TEXT, TEXT_MUTED};
+use crate::layout::classify_width;
 use crate::state::file_history::{FileHistoryResult, FileHistoryState};
 use crate::text_width::cursor_cell_offset;
 
 // ---------------------------------------------------------------------------
-// Colors (Flexoki palette)
+// Colors (Flexoki palette — screen-specific)
 // ---------------------------------------------------------------------------
 
-const TEXT: PackedRgba = PackedRgba::rgb(0xCE, 0xCD, 0xC3); // tx
-const TEXT_MUTED: PackedRgba = PackedRgba::rgb(0x87, 0x87, 0x80); // tx-2
-const BG_SURFACE: PackedRgba = PackedRgba::rgb(0x28, 0x28, 0x24); // bg-2
-const ACCENT: PackedRgba = PackedRgba::rgb(0xDA, 0x70, 0x2C); // orange
 const GREEN: PackedRgba = PackedRgba::rgb(0x87, 0x9A, 0x39); // green
 const CYAN: PackedRgba = PackedRgba::rgb(0x3A, 0xA9, 0x9F); // cyan
 const YELLOW: PackedRgba = PackedRgba::rgb(0xD0, 0xA2, 0x15); // yellow
@@ -53,6 +52,7 @@ pub fn render_file_history(
         return; // Terminal too small.
     }
 
+    let bp = classify_width(area.width);
     let x = area.x;
     let max_x = area.right();
     let width = area.width;
@@ -105,7 +105,7 @@ pub fn render_file_history(
     }
 
     // --- MR list ---
-    render_mr_list(frame, result, state, x, y, width, list_height);
+    render_mr_list(frame, result, state, x, y, width, list_height, bp);
 
     // --- Hint bar ---
     render_hint_bar(frame, x, hint_y, max_x);
@@ -248,6 +248,33 @@ fn render_summary(frame: &mut Frame<'_>, result: &FileHistoryResult, x: u16, y:
     frame.print_text_clipped(x + 1, y, &summary, style, max_x);
 }
 
+/// Responsive truncation widths for file history MR rows.
+const fn fh_title_max(bp: Breakpoint) -> usize {
+    match bp {
+        Breakpoint::Xs => 15,
+        Breakpoint::Sm => 25,
+        Breakpoint::Md => 35,
+        Breakpoint::Lg | Breakpoint::Xl => 55,
+    }
+}
+
+const fn fh_author_max(bp: Breakpoint) -> usize {
+    match bp {
+        Breakpoint::Xs | Breakpoint::Sm => 8,
+        Breakpoint::Md | Breakpoint::Lg | Breakpoint::Xl => 12,
+    }
+}
+
+const fn fh_disc_max(bp: Breakpoint) -> usize {
+    match bp {
+        Breakpoint::Xs => 25,
+        Breakpoint::Sm => 40,
+        Breakpoint::Md => 60,
+        Breakpoint::Lg | Breakpoint::Xl => 80,
+    }
+}
+
+#[allow(clippy::too_many_arguments)]
 fn render_mr_list(
     frame: &mut Frame<'_>,
     result: &FileHistoryResult,
@@ -256,10 +283,14 @@ fn render_mr_list(
     start_y: u16,
     width: u16,
     height: usize,
+    bp: Breakpoint,
 ) {
     let max_x = x + width;
     let offset = state.scroll_offset as usize;
 
+    let title_max = fh_title_max(bp);
+    let author_max = fh_author_max(bp);
+
     for (i, mr) in result
         .merge_requests
         .iter()
@@ -315,8 +346,8 @@ fn render_mr_list(
         };
         let after_iid = frame.print_text_clipped(after_icon, y, &iid_str, ref_style, max_x);
 
-        // Title (truncated).
-        let title = truncate_str(&mr.title, 35);
+        // Title (responsive truncation).
+        let title = truncate_str(&mr.title, title_max);
         let title_style = Cell {
             fg: TEXT,
             bg: sel_bg,
@@ -324,10 +355,10 @@ fn render_mr_list(
         };
         let after_title = frame.print_text_clipped(after_iid + 1, y, &title, title_style, max_x);
 
-        // @author + change_type
+        // @author + change_type (responsive author width).
         let meta = format!(
             "@{} {}",
-            truncate_str(&mr.author_username, 12),
+            truncate_str(&mr.author_username, author_max),
             mr.change_type
         );
         let meta_style = Cell {
@@ -339,13 +370,11 @@ fn render_mr_list(
     }
 
     // Inline discussion snippets (rendered beneath MRs when toggled on).
-    // For simplicity, discussions are shown as a separate block after the MR list
-    // in this initial implementation. Full inline rendering (grouped by MR) is
-    // a follow-up enhancement.
     if state.show_discussions && !result.discussions.is_empty() {
-        let disc_start_y = start_y + result.merge_requests.len().min(height) as u16;
-        let remaining = height.saturating_sub(result.merge_requests.len().min(height));
-        render_discussions(frame, result, x, disc_start_y, max_x, remaining);
+        let visible_mrs = result.merge_requests.len().saturating_sub(offset).min(height);
+        let disc_start_y = start_y + visible_mrs as u16;
+        let remaining = height.saturating_sub(visible_mrs);
+        render_discussions(frame, result, x, disc_start_y, max_x, remaining, bp);
     }
 }
 
@@ -356,11 +385,14 @@ fn render_discussions(
     start_y: u16,
     max_x: u16,
     max_rows: usize,
+    bp: Breakpoint,
 ) {
     if max_rows == 0 {
         return;
     }
 
+    let disc_max = fh_disc_max(bp);
+
     let sep_style = Cell {
         fg: TEXT_MUTED,
         ..Cell::default()
@@ -390,7 +422,7 @@ fn render_discussions(
             author_style,
             max_x,
         );
-        let snippet = truncate_str(&disc.body_snippet, 60);
+        let snippet = truncate_str(&disc.body_snippet, disc_max);
         frame.print_text_clipped(after_author, y, &snippet, disc_style, max_x);
     }
 }