Fix Windows-unsafe artifact filenames and enforce safe timestamp format

scripts/agent/run-scheduler-cycle.mjs

@@ -889,6 +889,7 @@ async function main() {
     schedulerRunState.lock_deferral = null;
     await writeRunState(runStatePath, schedulerRunState);
     const runArtifactSince = new Date().toISOString();
+    const runArtifactTimestamp = ts();
     const runStartMs = Date.parse(runArtifactSince);
     const outputChunks = [];
 
@@ -904,6 +905,7 @@ async function main() {
       SCHEDULER_CADENCE: cadence,
       SCHEDULER_PROMPT_PATH: promptPath,
       SCHEDULER_MEMORY_FILE: memoryFile,
+      SCHEDULER_RUN_TIMESTAMP: runArtifactTimestamp,
     };
 
     if (schedulerConfig.memoryPolicy.retrieveCommand) {

scripts/agent/verify-run-artifacts.mjs

@@ -133,6 +133,14 @@ function getMatchingArtifacts(files, { expectedPrefix, session }) {
   return files.filter((file) => file.name.startsWith(expectedPrefix));
 }
 
+function findInvalidFilenameCharacters(files) {
+  // Windows-invalid filename characters: <>:"/\|?*
+  const invalidCharRe = /[<>:"/\\|?*]/;
+  return files
+    .filter((file) => invalidCharRe.test(file.name))
+    .map((file) => file.name);
+}
+
 async function hasValidArtifactStructure(files, artifact) {
   for (const file of files) {
     const content = await fs.readFile(file.filePath, 'utf8').catch(() => '');
@@ -336,6 +344,11 @@ async function main() {
       continue;
     }
 
+    const invalidFilenames = findInvalidFilenameCharacters(matchingArtifacts);
+    if (invalidFilenames.length) {
+      missing.push(`${artifact.dir}: invalid filename characters for cross-platform sync in ${invalidFilenames.join(', ')}`);
+    }
+
     const hasValidStructure = await hasValidArtifactStructure(matchingArtifacts, artifact);
     if (!hasValidStructure) {
       missing.push(`${artifact.dir}: ${artifact.structureHint}`);