fix(sqlite): enforce integer session metadata

packages/session-persistence/session-persistence-jsonl/src/format.ts

@@ -84,6 +84,8 @@ function isHeaderLine(value: unknown): value is HeaderLine {
     && typeof (value as { version?: unknown }).version === 'number'
     && typeof (value as { id?: unknown }).id === 'string'
     && typeof (value as { createdAt?: unknown }).createdAt === 'number'
+    && Number.isSafeInteger((value as { createdAt: number }).createdAt)
+    && (value as { createdAt: number }).createdAt >= 0
     && typeof (value as { delegationDepth?: unknown }).delegationDepth === 'number'
     && Number.isSafeInteger((value as { delegationDepth: number }).delegationDepth)
     && (value as { delegationDepth: number }).delegationDepth >= 0

packages/session-persistence/session-persistence-jsonl/tests/jsonl.spec.ts

@@ -559,6 +559,21 @@ describe('SessionPersistenceJsonl: scanLog unit', () => {
     expect(() => scanLog(Buffer.from('{"type":"event"}\n'))).toThrow(/session header/)
   })
 
+  it.each([
+    ['fractional', 1.5],
+    ['negative', -1],
+    ['unsafe', Number.MAX_SAFE_INTEGER + 1],
+  ])('rejects a session header with a %s createdAt', (_label, createdAt) => {
+    const log = JSON.stringify({
+      type: 'session',
+      version: 0,
+      id: 'invalid-created-at',
+      createdAt,
+      delegationDepth: 0,
+    }) + '\n'
+    expect(() => scanLog(Buffer.from(log))).toThrow(/session header/)
+  })
+
   it.each([
     ['missing', undefined],
     ['a string', '1'],