fix: align AGENTS.md template section names with post-compaction extraction (#25029)

The official AGENTS.md template uses '## Every Session' and '## Safety',
but post-compaction context extraction expects '## Session Startup' and
'## Red Lines'. This causes workspaces using the official template to
lose startup context and safety rules after compaction.

Changes:
- Rename template sections to match code expectations (both EN and zh-CN)
- Add legacy fallback: code now tries 'Every Session'/'Safety' when
  'Session Startup'/'Red Lines' are not found (backward compatible)
- Add tests for legacy fallback and precedence when both exist

docs/reference/templates/AGENTS.md

@@ -13,7 +13,7 @@ This folder is home. Treat it that way.
 
 If `BOOTSTRAP.md` exists, that's your birth certificate. Follow it, figure out who you are, then delete it. You won't need it again.
 
-## Every Session
+## Session Startup
 
 Before doing anything else:
 
@@ -52,7 +52,7 @@ Capture what matters. Decisions, context, things to remember. Skip the secrets u
 - When you make a mistake → document it so future-you doesn't repeat it
 - **Text > Brain** 📝
 
-## Safety
+## Red Lines
 
 - Don't exfiltrate private data. Ever.
 - Don't run destructive commands without asking.

docs/zh-CN/reference/templates/AGENTS.md

@@ -19,7 +19,7 @@ x-i18n:
 
 如果 `BOOTSTRAP.md` 存在，那就是你的"出生证明"。按照它的指引，弄清楚你是谁，然后删除它。你不会再需要它了。
 
-## 每次会话
+## 会话启动
 
 在做任何事情之前：
 
@@ -58,7 +58,7 @@ x-i18n:
 - 当你犯了错误 → 记录下来，这样未来的你不会重蹈覆辙
 - **文件 > 大脑** 📝
 
-## 安全
+## 红线
 
 - 不要泄露隐私数据。绝对不要。
 - 不要在未询问的情况下执行破坏性命令。

src/agents/pi-extensions/compaction-safeguard.ts

@@ -522,6 +522,7 @@ function appendSummarySection(summary: string, section: string): string {
 /**
  * Read and format critical workspace context for compaction summary.
  * Extracts "Session Startup" and "Red Lines" from AGENTS.md.
+ * Falls back to legacy names "Every Session" and "Safety".
  * Limited to 2000 chars to avoid bloating the summary.
  */
 async function readWorkspaceContextForSummary(): Promise<string> {
@@ -546,7 +547,12 @@ async function readWorkspaceContextForSummary(): Promise<string> {
         fs.closeSync(opened.fd);
       }
     })();
-    const sections = extractSections(content, ["Session Startup", "Red Lines"]);
+    // Accept legacy section names ("Every Session", "Safety") as fallback
+    // for backward compatibility with older AGENTS.md templates.
+    let sections = extractSections(content, ["Session Startup", "Red Lines"]);
+    if (sections.length === 0) {
+      sections = extractSections(content, ["Every Session", "Safety"]);
+    }
 
     if (sections.length === 0) {
       return "";

src/auto-reply/reply/post-compaction-context.test.ts

@@ -226,4 +226,57 @@ Read WORKFLOW.md on startup.
     expect(result).not.toBeNull();
     expect(result).toContain("Current time:");
   });
+
+  it("falls back to legacy section names (Every Session / Safety)", async () => {
+    const content = `# Rules
+
+## Every Session
+
+Read SOUL.md and USER.md.
+
+## Safety
+
+Don't exfiltrate private data.
+
+## Other
+
+Ignore this.
+`;
+    fs.writeFileSync(path.join(tmpDir, "AGENTS.md"), content);
+    const result = await readPostCompactionContext(tmpDir);
+    expect(result).not.toBeNull();
+    expect(result).toContain("Every Session");
+    expect(result).toContain("Read SOUL.md");
+    expect(result).toContain("Safety");
+    expect(result).toContain("Don't exfiltrate");
+    expect(result).not.toContain("Other");
+  });
+
+  it("prefers new section names over legacy when both exist", async () => {
+    const content = `# Rules
+
+## Session Startup
+
+New startup instructions.
+
+## Every Session
+
+Old startup instructions.
+
+## Red Lines
+
+New red lines.
+
+## Safety
+
+Old safety rules.
+`;
+    fs.writeFileSync(path.join(tmpDir, "AGENTS.md"), content);
+    const result = await readPostCompactionContext(tmpDir);
+    expect(result).not.toBeNull();
+    expect(result).toContain("New startup instructions");
+    expect(result).toContain("New red lines");
+    expect(result).not.toContain("Old startup instructions");
+    expect(result).not.toContain("Old safety rules");
+  });
 });

src/auto-reply/reply/post-compaction-context.ts

@@ -53,9 +53,14 @@ export async function readPostCompactionContext(
       }
     })();
 
-    // Extract "## Session Startup" and "## Red Lines" sections
+    // Extract "## Session Startup" and "## Red Lines" sections.
+    // Also accept legacy names "Every Session" and "Safety" for backward
+    // compatibility with older AGENTS.md templates.
     // Each section ends at the next "## " heading or end of file
-    const sections = extractSections(content, ["Session Startup", "Red Lines"]);
+    let sections = extractSections(content, ["Session Startup", "Red Lines"]);
+    if (sections.length === 0) {
+      sections = extractSections(content, ["Every Session", "Safety"]);
+    }
 
     if (sections.length === 0) {
       return null;