fix(agent-core-v2): re-remind AGENTS.md after compaction and report enabled flags

Sessions no longer fail to start when the subagent model pool is
misconfigured. The fork context notice is delivered as a reminder
instead of being prepended to the prompt. Git status is parsed with -z
so non-ASCII paths survive. Subdirectory AGENTS.md discoveries are
re-injected after context compaction, and session_started telemetry
carries the enabled experimental flag ids.

Author: elkaix

GOAL.md

@@ -810,7 +810,14 @@ export async function applyExperimentalFeatureChanges(
     if (changes.some((change) => change.id === 'tower')) {
       host.showNotice('Tower mode takes effect after restarting Pythinker Code.');
     }
-    host.track('experimental_features_apply', { changed: changes.length });
+    host.track('experimental_features_apply', {
+      changed: changes.length,
+      flags: features
+        .filter((feature) => feature.enabled)
+        .map((feature) => feature.id)
+        .toSorted()
+        .join(','),
+    });
   } catch (error) {
     host.showError(`Failed to update experimental features: ${formatErrorMessage(error)}`);
   }

apps/pythinker-code/src/tui/commands/config.ts

@@ -98,13 +98,30 @@ describe('experimental feature command handlers', () => {
     expect(host.mountEditorReplacement).not.toHaveBeenCalled();
     expect(host.track).toHaveBeenCalledWith('experimental_features_apply', {
       changed: 1,
+      flags: '',
     });
     expect(host.showStatus).not.toHaveBeenCalledWith(
       'Experimental features updated.',
       darkColors.success,
     );
   });
 
+  it('reports the post-apply enabled flag set in telemetry', async () => {
+    const host = makeHost();
+    host.harness.getExperimentalFeatures.mockResolvedValue([
+      feature({ id: 'wait_for', enabled: true }),
+      feature({ id: 'subagent_fork', enabled: true }),
+      feature({ id: 'tower', enabled: false }),
+    ]);
+
+    await applyExperimentalFeatureChanges(host, [{ id: 'subagent_fork', enabled: true }]);
+
+    expect(host.track).toHaveBeenCalledWith('experimental_features_apply', {
+      changed: 1,
+      flags: 'subagent_fork,wait_for',
+    });
+  });
+
   it('does not write config when there are no drafted changes', async () => {
     const host = makeHost();
 

apps/pythinker-code/test/tui/commands/experiments.test.ts

@@ -27,7 +27,7 @@
 // references become '(circular)', and class instances collapse to a '(ClassName)'
 // marker — the wire shape of an entry is the JSON projection of the type here.
 //
-// Index (App: 0 keys · Workspace: 6 keys · Session: 10 keys · Agent: 86 keys)
+// Index (App: 0 keys · Workspace: 6 keys · Session: 10 keys · Agent: 87 keys)
 //   App
 //   Workspace
 //     workspaceDirs.ephemeralDirs          src/workspace/workspaceDirs/workspaceDirsService.ts
@@ -56,6 +56,7 @@
 //     agentPlugin.sessionStartRefreshPending          src/agent/plugin/agentPluginService.ts
 //     agentsMdReminder.cwd                            src/agent/agentsMdReminder/agentsMdReminderService.ts
 //     agentsMdReminder.known                          src/agent/agentsMdReminder/agentsMdReminderService.ts
+//     agentsMdReminder.pending                        src/agent/agentsMdReminder/agentsMdReminderService.ts
 //     agentsMdReminder.seeded                         src/agent/agentsMdReminder/agentsMdReminderService.ts
 //     contextMemory                                   src/agent/contextMemory/contextOps.ts
 //     contextProjector.lastRepairSignature            src/agent/contextProjector/contextProjectorService.ts
@@ -1300,6 +1301,7 @@ export interface AgentStateSnapshot {
   // src/agent/agentsMdReminder/agentsMdReminderService.ts
   'agentsMdReminder.cwd': string | undefined;
   'agentsMdReminder.known': Set<string>;
+  'agentsMdReminder.pending': Set<string>;
   'agentsMdReminder.seeded': boolean;
   // src/agent/contextMemory/contextOps.ts
   // replayable · durable · undoable — folds: ContextAppendMessage, ContextAppendLoopEvent, ContextClear, ContextApplyCompaction