feat: company portability — export/import companies and agents

Add company export, import preview, and import endpoints with manifest-
based bundle format. Includes URL key utilities for agents and projects,
collision detection/rename strategies, and secret requirement tracking.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/shared/src/project-url-key.ts

@@ -0,0 +1,16 @@
+const PROJECT_URL_KEY_DELIM_RE = /[^a-z0-9]+/g;
+const PROJECT_URL_KEY_TRIM_RE = /^-+|-+$/g;
+
+export function normalizeProjectUrlKey(value: string | null | undefined): string | null {
+  if (typeof value !== "string") return null;
+  const normalized = value
+    .trim()
+    .toLowerCase()
+    .replace(PROJECT_URL_KEY_DELIM_RE, "-")
+    .replace(PROJECT_URL_KEY_TRIM_RE, "");
+  return normalized.length > 0 ? normalized : null;
+}
+
+export function deriveProjectUrlKey(name: string | null | undefined, fallback?: string | null): string {
+  return normalizeProjectUrlKey(name) ?? normalizeProjectUrlKey(fallback) ?? "project";
+}