refactor(migration): remove obsolete mirror extraction tooling

- delete extraction scripts that depended on the removed local mirror
- remove stale extract npm scripts and migration-brief references
- drop the old mirror ignore rule from .gitignore
- update reports and redirect reasons to use live-source wording

.gitignore

@@ -58,6 +58,3 @@ temp/
 .DS_Store
 Thumbs.db
 Desktop.ini
-
-# Read-only wget mirror used as migration source material
-/www.azinstitute4autism.com/