chore: remove obsolete APIs (register, probe, n8n, videos, people)

- Remove /api/v1/register (replaced by /api/v1/files/register)
- Remove /api/v1/probe (replaced by /api/v1/files/:uuid)
- Remove /api/v1/n8n/... (n8n workflow only)
- Remove /api/v1/unregister (high risk)
- Remove /api/v1/videos list (replaced by /api/v1/files)
- Remove /api/v1/people (merged into /api/v1/identities)
- Clean up dead code and unused structs

Cargo.lock

@@ -2340,7 +2340,7 @@ dependencies = [
 
 [[package]]
 name = "momentry_core"
-version = "0.1.0"
+version = "1.0.0"
 dependencies = [
  "aes-gcm",
  "anyhow",