fix(extract): make receipt shortRunId canonical under slugifySegment (#3443)

shortRunId() truncated run ids to their first 8 chars, so propose_takes
run ids ('propose-<timestamp>-<uuid>') shortened to 'propose-' with a
trailing hyphen. slugifySegment() strips boundary hyphens during repo
sync, so the DB receipt slug and its Git-backed markdown slug disagreed
— writing the receipt through to the system-of-record repo created a
normalized sibling/collision instead of materializing the existing page.

shortRunId now trims boundary hyphens after truncation (invariant:
slugifySegment(shortRunId(x)) === shortRunId(x)), with a non-empty
fallback for pathological all-separator prefixes. All other run-id
families (atoms-, efacts-, concepts-, ecf-) are unchanged.

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

src/core/extract/receipt-writer.ts

@@ -85,11 +85,21 @@ const RUN_ID_SHORT_LEN = 8;
 /**
  * Truncate a run id to the standard 8-char short form used in slug
  * paths. Idempotent — passing an already-short id returns it unchanged.
- * Non-hex / non-alphanumeric chars survive (op-checkpoint ids may
- * include dashes or other separators).
+ * Non-hex / non-alphanumeric chars survive INSIDE the short form
+ * (op-checkpoint ids may include dashes or other separators), but
+ * boundary hyphens are trimmed (#3443): `slugifySegment()` strips
+ * leading/trailing hyphens during repo sync, so a short form like
+ * 'propose-' (from propose-<timestamp> run ids) made the DB receipt
+ * slug and its Git-backed slug disagree — writing the receipt through
+ * to the repo created a normalized sibling instead of materializing
+ * the existing page. Invariant: slugifySegment(shortRunId(x)) ===
+ * shortRunId(x) for slug-safe run ids.
  */
 export function shortRunId(runId: string): string {
-  return runId.slice(0, RUN_ID_SHORT_LEN);
+  // ponytail: truncation-based discrimination is only as good as the run id's
+  // first 8 chars; families that need per-run uniqueness must front-load it.
+  const short = runId.slice(0, RUN_ID_SHORT_LEN).replace(/^-+|-+$/g, '');
+  return short || (runId ? 'run' : '');
 }
 
 /**

test/extract/receipt-writer.test.ts

@@ -20,6 +20,7 @@ import {
   writeReceipt,
   type ExtractReceiptInput,
 } from '../../src/core/extract/receipt-writer.ts';
+import { slugifySegment } from '../../src/core/sync.ts';
 
 const BASE_INPUT: ExtractReceiptInput = {
   kind: 'facts.conversation',
@@ -81,6 +82,31 @@ describe('shortRunId / dateFromIso — pure helpers', () => {
     expect(shortRunId('op_check_abc')).toBe('op_check');
   });
 
+  // #3443 — a short form ending in '-' (e.g. propose-<timestamp> run ids)
+  // desynced the DB receipt slug from its Git-backed slug: slugifySegment()
+  // strips boundary hyphens during repo sync, so the write-through created a
+  // normalized sibling instead of materializing the existing page.
+  test('shortRunId is canonical under slugifySegment for every receipt-producing run-id family (#3443)', () => {
+    const familyRunIds = [
+      'propose-20260724103000-ab12cd34',           // cycle/propose-takes.ts
+      `atoms-${Date.now().toString(36)}-pers`,     // cycle/extract-atoms.ts
+      `efacts-${Date.now().toString(36)}-pers`,    // cycle/extract-facts.ts
+      `concepts-${Date.now().toString(36)}`,       // cycle/synthesize-concepts.ts
+      `ecf-${Date.now().toString(36)}-pers`,       // extract-conversation-facts.ts
+    ];
+    for (const runId of familyRunIds) {
+      const short = shortRunId(runId);
+      expect(slugifySegment(short)).toBe(short);
+      expect(short.length).toBeGreaterThan(0);
+    }
+  });
+
+  test('shortRunId trims boundary hyphens introduced by truncation', () => {
+    expect(shortRunId('propose-20260724103000-ab12cd34')).toBe('propose');
+    // Pathological all-separator prefix still yields a non-empty segment.
+    expect(shortRunId('--------tail')).toBe('run');
+  });
+
   test('dateFromIso extracts YYYY-MM-DD prefix', () => {
     expect(dateFromIso('2026-05-27T14:30:00Z')).toBe('2026-05-27');
     expect(dateFromIso('2026-05-27T14:30:00.123456Z')).toBe('2026-05-27');