in-memory database functionality does not include seeding

**Describe the bug**
the in-memory database functionality does not include seeding

**To Reproduce**
run the server with DATABASE_TYPE `memory`

**Expected behavior**
seeding occurs

**Logs**
```
2025/06/05 07:21:17 Starting MCP Registry Application v0.1.0 (commit: undefined)
2025/06/05 07:21:17 HTTP server starting on :8080
```

**Additional context**
related to #63, #74
