fix: set verb.source/target to entity UUID instead of NounType

relate() was setting verb.source = fromEntity.type (a NounType like
"concept") instead of the entity UUID. Cortex's graph index indexes by
verb.source, so lookups by UUID found nothing — causing in-session
reads to return 0 results.

Also fixes:
- PathResolver calling private getIdsFromChunks() → public getIds()
- Plugin auto-detection removed; cortex loads only via explicit config
- GraphVerb types accept number timestamps and sourceId/targetId aliases
- Dead autoDetect() method removed from PluginRegistry
- In-session regression tests added for getRelations after relate()

src/vfs/PathResolver.ts

@@ -214,7 +214,7 @@ export class PathResolver {
     try {
       // Direct O(log n) query to roaring bitmap index
       // This queries the 'path' field in VFS entity metadata
-      const ids = await metadataIndex.getIdsFromChunks('path', path)
+      const ids = await metadataIndex.getIds('path', path)
 
       if (ids.length === 0) {
         this.metadataIndexMisses++