Strip markdown headings and "Plan:" prefix from GOAL column in fabro ps (#111)

This change cleans up the `GOAL` column in `fabro ps` output by
stripping common markdown noise before displaying goal text.
Specifically, `truncate_goal` now removes leading `#` heading markers
and an optional `Plan:` prefix (applied in order, so `## Plan: migrate
DB` correctly becomes `migrate DB`). Whitespace is trimmed after each
strip step to avoid leading spaces in the result.

As a minor refactor, the truncation logic was extracted into a
standalone `truncate_str` helper. This allows `truncate_goal` to
delegate cleanly after preprocessing, and also lets the workflow name
column (which doesn't need heading/prefix stripping) call `truncate_str`
directly. Five new unit tests cover the stripping behavior, combined
stripping, passthrough of plain text, and that truncation still applies
correctly after stripping.

### Fabro Details

<details>
<summary>Ran 9 stages in 9m 0s for $1.17</summary>

| Stage | Duration | Cost | Retries |
|---|---|---|---|
| start | 0s | – | 0 |
| toolchain | 0s | – | 0 |
| preflight_compile | 1m 10s | – | 0 |
| preflight_lint | 12s | – | 0 |
| implement | 2m 28s | $0.42 | 0 |
| simplify_opus | 3m 20s | $0.75 | 0 |
| simplify_gpt | 0s | – | 0 |
| verify | 1m 20s | – | 0 |
| fmt | 1s | – | 0 |
| **Total** | **9m 0s** | **$1.17** | **0** |

</details>

<details>
<summary>Ran <code>ImplementAndSimplify.fabro</code> (12 nodes and 15
edges)</summary>

```dot
digraph ImplementAndSimplify {
    graph [
        goal="Implement and simplify",
        model_stylesheet="
            * { backend: api; model: claude-opus-4-6;}
        "
    ]
    rankdir=LR

    start [shape=Mdiamond, label="Start"]
    exit  [shape=Msquare, label="Exit"]

    toolchain         [label="Toolchain", shape=parallelogram, script="command -v cargo >/dev/null || { curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && sudo ln -sf $HOME/.cargo/bin/* /usr/local/bin/; }; cargo --version 2>&1", max_retries=0]
    preflight_compile [label="Preflight Compile", shape=parallelogram, script="cargo check -q --workspace 2>&1", max_retries=0]
    preflight_lint    [label="Preflight Lint", shape=parallelogram, script="cargo clippy -q --workspace -- -D warnings 2>&1", max_retries=0]
    fix_lints         [label="Fix Lints", prompt="The preflight lint step failed. Read the build output from context and fix all clippy lint warnings.", max_visits=3]
    implement         [label="Implement", prompt="Read the plan file referenced in the goal and implement every step. Make all the code changes described in the plan. Use red/green TDD."]
    simplify_opus     [label="Simplify (Opus)", prompt="@prompts/simplify.md"]
    simplify_gpt      [label="Simplify (GPT-54)", prompt="@prompts/simplify.md", model="gpt-54"]
    verify            [label="Verify", shape=parallelogram, script="cargo clippy -q --workspace -- -D warnings 2>&1 && cargo nextest run --cargo-quiet --workspace --status-level fail 2>&1", goal_gate=true, retry_target="fixup"]
    fixup             [label="Fixup", prompt="The verify step failed. Read the build output from context and fix all clippy lint warnings and test failures.", max_visits=3]
    fmt               [label="Format", shape=parallelogram, script="cargo fmt --all 2>&1", max_retries=0]

    start -> toolchain
    toolchain -> preflight_compile [condition="outcome=success"]
    toolchain -> exit
    preflight_compile -> preflight_lint [condition="outcome=success"]
    preflight_compile -> exit
    preflight_lint -> implement [condition="outcome=success"]
    preflight_lint -> fix_lints
    fix_lints -> preflight_lint
    implement -> simplify_opus -> simplify_gpt -> verify
    verify -> fmt   [condition="outcome=success"]
    verify -> fixup
    fixup -> verify
    fmt -> exit
}

```

</details>

⚒️ Generated with [Fabro](https://fabro.sh)

---------

Co-authored-by: Fabro <noreply@fabro.sh>

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

@@ -228,11 +228,17 @@ fn short_run_id(id: &str) -> &str {
 
 fn truncate_goal(goal: &str, max_len: usize) -> String {
     let line = goal.lines().next().unwrap_or("");
-    let char_count = line.chars().count();
+    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)
+}
+
+fn truncate_str(s: &str, max_len: usize) -> String {
+    let char_count = s.chars().count();
     if char_count <= max_len {
-        return line.to_string();
+        return s.to_string();
     }
-    let truncated: String = line.chars().take(max_len - 3).collect();
+    let truncated: String = s.chars().take(max_len - 3).collect();
     format!("{truncated}...")
 }
 
@@ -404,7 +410,7 @@ fn df_from(args: &DfArgs, data_dir: &Path, runs_base: &Path, logs_base: &Path) -
             };
             vec![
                 short_run_id(&detail.run_id).cell(),
-                truncate_goal(&detail.workflow_name, 16).cell(),
+                truncate_str(&detail.workflow_name, 16).cell(),
                 detail.status.to_string().cell(),
                 age.cell().justify(Justify::Right),
                 size_display.cell().justify(Justify::Right),
@@ -588,4 +594,34 @@ mod tests {
         assert_eq!(format_size(1024), "1.0 KB");
         assert_eq!(format_size(1024 * 1024), "1.0 MB");
     }
+
+    #[test]
+    fn truncate_goal_strips_markdown_headings() {
+        assert_eq!(truncate_goal("## Fix bug", 50), "Fix bug");
+        assert_eq!(truncate_goal("# Title", 50), "Title");
+        assert_eq!(truncate_goal("### Deep heading", 50), "Deep heading");
+    }
+
+    #[test]
+    fn truncate_goal_strips_plan_prefix() {
+        assert_eq!(truncate_goal("Plan: do stuff", 50), "do stuff");
+    }
+
+    #[test]
+    fn truncate_goal_strips_heading_and_plan_prefix() {
+        assert_eq!(truncate_goal("## Plan: migrate DB", 50), "migrate DB");
+    }
+
+    #[test]
+    fn truncate_goal_plain_text_unchanged() {
+        assert_eq!(truncate_goal("Fix the login bug", 50), "Fix the login bug");
+    }
+
+    #[test]
+    fn truncate_goal_still_truncates_after_stripping() {
+        assert_eq!(
+            truncate_goal("## A long goal description", 10),
+            "A long ..."
+        );
+    }
 }