fix: close PI-140 cutover gaps

Back up unknown legacy Agents, reconnect settled Conversation observation, remove remaining active repository residue, and restore the bundled Python verifier import.

electron/coding-projects/migration.ts

@@ -1,10 +1,12 @@
 import {
   copyFile,
   mkdir,
+  readdir,
   readFile,
   rm,
   unlink,
 } from 'node:fs/promises';
+import type { Dirent } from 'node:fs';
 import path from 'node:path';
 import type { ProductModelRef } from '../coding-runtime/contracts';
 import {
@@ -93,12 +95,22 @@ async function snapshotLegacyAgentFiles(
     path.basename(entry.relativePath),
     entry.content,
   ]));
+  let entries: Dirent[];
+  try {
+    entries = await readdir(agentDirectory, { withFileTypes: true });
+  } catch (error) {
+    if (isMissing(error)) return [];
+    throw error;
+  }
   const snapshots: AgentFileSnapshot[] = [];
-  for (const [fileName, expectedContent] of expected) {
+  for (const entry of entries
+    .filter((candidate) => candidate.isFile())
+    .sort((left, right) => left.name.localeCompare(right.name))) {
+    const fileName = entry.name;
     const filePath = path.join(agentDirectory, fileName);
     const content = await readOptionalText(filePath);
     if (content === null) continue;
-    const generated = expectedContent === content;
+    const generated = expected.get(fileName) === content;
     if (generated) {
       snapshots.push({ fileName, filePath, content, generated });
       continue;