fix(cli): flex-col min-width clamping and formatting consistency

- render.rs: clamp flex column width to min(min_flex, natural) instead
  of a hardcoded 20, preventing layout overflow when natural width is
  small; rewrites flex_width test to be terminal-independent
- list/issues.rs: adopt .flex_col() builder on table construction
- list/mrs.rs, list/notes.rs: consolidate multi-line StyledCell::styled
  calls to single-line format
- explain.rs: adopt flex_width() for related-issue title truncation,
  consolidate multi-line formatting

src/cli/commands/list/issues.rs

@@ -359,7 +359,10 @@ pub fn print_list_issues(result: &ListResult) {
     }
     headers.extend(["Assignee", "Labels", "Disc", "Updated"]);
 
-    let mut table = LoreTable::new().headers(&headers).align(0, Align::Right).flex_col(1);
+    let mut table = LoreTable::new()
+        .headers(&headers)
+        .align(0, Align::Right)
+        .flex_col(1);
 
     for issue in &result.issues {
         let title = issue.title.clone();