fix(formatters): use divider() in issue/list.ts and escape Seer text in headings

- issue/list.ts: replace inline muted("─".repeat(n)) with divider(n) from
  markdown.ts — the helper already exists and is re-exported via the
  formatters index; inlining it duplicated the helper logic
- seer.ts buildRootCauseMarkdown: escape cause.description with
  escapeMarkdownInline() before embedding in the '### Cause #N: ...' heading
- seer.ts formatSolution: escape solution.data.one_line_summary with
  escapeMarkdownInline() before embedding in '**Summary:** ...' bold text
  — Seer AI-generated text can contain underscores, asterisks, and backticks
  which the markdown parser would interpret as emphasis or code spans

Author: BYK

src/commands/issue/list.ts

@@ -35,6 +35,7 @@ import {
   ValidationError,
 } from "../../lib/errors.js";
 import {
+  divider,
   type FormatShortIdOptions,
   formatIssueListHeader,
   formatIssueRow,
@@ -117,7 +118,7 @@ function writeListHeader(
 ): void {
   stdout.write(`${title}:\n\n`);
   stdout.write(muted(`${formatIssueListHeader(isMultiProject)}\n`));
-  stdout.write(muted(`${"─".repeat(isMultiProject ? 96 : 80)}\n`));
+  stdout.write(`${divider(isMultiProject ? 96 : 80)}\n`);
 }
 
 /** Issue with formatting options attached */

src/lib/formatters/seer.ts

@@ -12,7 +12,7 @@ import type {
 } from "../../types/seer.js";
 import { SeerError } from "../errors.js";
 import { cyan } from "./colors.js";
-import { renderMarkdown } from "./markdown.js";
+import { escapeMarkdownInline, renderMarkdown } from "./markdown.js";
 
 // Spinner Frames
 
@@ -107,7 +107,9 @@ export function getProgressMessage(state: AutofixState): string {
 function buildRootCauseMarkdown(cause: RootCause, index: number): string {
   const lines: string[] = [];
 
-  lines.push(`### Cause #${index}: ${cause.description}`);
+  lines.push(
+    `### Cause #${index}: ${escapeMarkdownInline(cause.description ?? "")}`
+  );
   lines.push("");
 
   if (cause.relevant_repos && cause.relevant_repos.length > 0) {
@@ -257,7 +259,9 @@ export function formatSolution(solution: SolutionArtifact): string {
   lines.push("## Solution");
   lines.push("");
 
-  lines.push(`**Summary:** ${solution.data.one_line_summary}`);
+  lines.push(
+    `**Summary:** ${escapeMarkdownInline(solution.data.one_line_summary ?? "")}`
+  );
   lines.push("");
 
   if (solution.data.steps.length > 0) {