fix(plan): perkuat fixture test log agar benar-benar uji squash_log

Ditemukan lewat trace manual (bukan implementer): fixture lama cuma
punya 1 baris berpola error, di bawah ambang looks_log_shaped (>=3),
jadi tanpa sadar selalu jatuh ke squash_generic -- test tetap lulus
tapi tidak pernah menguji logika scoring/windowing squash_log sama
sekali. Tambah baris error/warning lagi supaya jalur squash_log
benar-benar terpakai.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/superpowers/plans/2026-07-16-context-compaction-overhaul.md

@@ -672,16 +672,28 @@ mod tests {
 
     #[test]
     fn log_like_output_keeps_error_lines_and_marks_omissions() {
+        // `looks_log_shaped` requires >= 3 lines matching error/warn/fail/
+        // panic/stack-frame patterns before routing to `squash_log` at
+        // all — a single error line isn't enough and would silently fall
+        // through to `squash_generic` instead, so this fixture needs at
+        // least 3 such lines, spread apart, to actually exercise
+        // squash_log's scoring/windowing logic (not just its fallback).
         let mut lines = vec!["build started".to_string()];
         for i in 0..200 {
             lines.push(format!("info: compiling module {i}"));
         }
+        lines.push("error: something failed early in the build".to_string());
+        for i in 0..200 {
+            lines.push(format!("info: compiling module {}", i + 200));
+        }
+        lines.push("warning: deprecated api used somewhere".to_string());
         lines.push("error: something failed at the end".to_string());
         let text = lines.join("\n");
         assert!(text.len() > SQUASH_FLOOR_BYTES);
 
         let result = apply("bash", &text);
 
+        assert!(result.contains("error: something failed early in the build"));
         assert!(result.contains("error: something failed at the end"));
         assert!(result.contains("lines omitted"));
         assert!(result.len() < text.len());