Unify goal prefix stripping into shared strip_goal_decoration() in fabro-util

Three places stripped markdown headings and `Plan:` prefixes from goals
with slightly different logic. Extract a shared function so all call sites
behave consistently, and fix `fabro run` which wasn't stripping at all.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/crates/fabro-cli/src/commands/run.rs

@@ -546,8 +546,8 @@ pub(crate) fn prepare_workflow(
 
     let goal = graph.goal();
     if !goal.is_empty() {
-        let first_line = goal.lines().next().unwrap_or(goal);
-        eprintln!("{} {first_line}\n", styles.bold.apply_to("Goal:"));
+        let stripped = fabro_util::text::strip_goal_decoration(goal);
+        eprintln!("{} {stripped}\n", styles.bold.apply_to("Goal:"));
     }
 
     print_diagnostics(&diagnostics, styles);

lib/crates/fabro-cli/src/commands/runs.rs

@@ -227,10 +227,7 @@ fn short_run_id(id: &str) -> &str {
 }
 
 fn truncate_goal(goal: &str, max_len: usize) -> String {
-    let line = goal.lines().next().unwrap_or("");
-    let line = line.trim_start_matches('#').trim();
-    let line = line.strip_prefix("Plan:").map(|s| s.trim()).unwrap_or(line);
-    truncate_str(line, max_len)
+    truncate_str(fabro_util::text::strip_goal_decoration(goal), max_len)
 }
 
 fn truncate_str(s: &str, max_len: usize) -> String {

lib/crates/fabro-util/src/lib.rs

@@ -4,4 +4,5 @@ pub mod path;
 pub mod redact;
 pub mod run_log;
 pub mod terminal;
+pub mod text;
 pub mod version;

lib/crates/fabro-util/src/text.rs

@@ -0,0 +1,60 @@
+/// Strip markdown heading prefixes and `Plan:` prefix from a goal string.
+///
+/// Takes the first line, removes all leading `#` characters, then strips
+/// a `Plan:` prefix if present. Returns a trimmed `&str` slice.
+pub fn strip_goal_decoration(goal: &str) -> &str {
+    let line = goal.lines().next().unwrap_or("");
+    let line = line.trim_start_matches('#').trim();
+    line.strip_prefix("Plan:").map(|s| s.trim()).unwrap_or(line)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn strips_h1() {
+        assert_eq!(strip_goal_decoration("# Title"), "Title");
+    }
+
+    #[test]
+    fn strips_h2() {
+        assert_eq!(strip_goal_decoration("## Fix bug"), "Fix bug");
+    }
+
+    #[test]
+    fn strips_h3() {
+        assert_eq!(strip_goal_decoration("### Deep heading"), "Deep heading");
+    }
+
+    #[test]
+    fn strips_plan_prefix() {
+        assert_eq!(strip_goal_decoration("Plan: do stuff"), "do stuff");
+    }
+
+    #[test]
+    fn strips_heading_and_plan_prefix() {
+        assert_eq!(strip_goal_decoration("## Plan: migrate DB"), "migrate DB");
+    }
+
+    #[test]
+    fn plain_text_unchanged() {
+        assert_eq!(
+            strip_goal_decoration("Fix the login bug"),
+            "Fix the login bug"
+        );
+    }
+
+    #[test]
+    fn takes_first_line() {
+        assert_eq!(
+            strip_goal_decoration("## Plan: First\n\nMore details"),
+            "First"
+        );
+    }
+
+    #[test]
+    fn empty_string() {
+        assert_eq!(strip_goal_decoration(""), "");
+    }
+}

lib/crates/fabro-workflows/src/pull_request.rs

@@ -33,20 +33,12 @@ impl PullRequestRecord {
 ///
 /// Uses the first line, truncated to 120 characters for readability.
 fn pr_title_from_goal(goal: &str) -> String {
-    let first_line = goal.lines().next().unwrap_or(goal);
-    let first_line = first_line
-        .strip_prefix("## ")
-        .or_else(|| first_line.strip_prefix("# "))
-        .unwrap_or(first_line);
-    let first_line = first_line
-        .strip_prefix("Plan:")
-        .map(|s| s.trim())
-        .unwrap_or(first_line);
-    if first_line.chars().count() > 120 {
-        let truncated: String = first_line.chars().take(119).collect();
+    let stripped = fabro_util::text::strip_goal_decoration(goal);
+    if stripped.chars().count() > 120 {
+        let truncated: String = stripped.chars().take(119).collect();
         format!("{truncated}…")
     } else {
-        first_line.to_string()
+        stripped.to_string()
     }
 }
 
@@ -866,10 +858,10 @@ mod tests {
     }
 
     #[test]
-    fn pr_title_does_not_strip_h3_prefix() {
+    fn pr_title_strips_h3_prefix() {
         assert_eq!(
             pr_title_from_goal("### Add Draft PR Mode"),
-            "### Add Draft PR Mode"
+            "Add Draft PR Mode"
         );
     }