feat(kb): fill brain from eslider portfolio, evidence gates green

- kb/index: index yaml seeds (knowledge-mesh, workspace catalogs) as leafs
- kblib: open_readonly no longer writes schema; INSTALL extensions helper
- facts/audit db: drop init_schema on read-only connection
- kb/eval: assert by text fragment not stale leaf ids; recall@5 = 1.0
- corpus: var/kb.lbug rebuilt with eslider/cv (4580 leafs) + ops facts

Confirmed facts now: eslider DevOps/25yr engineer (CV README x career-timeline)
+ 13 ops facts (docker ps x compose, ssh x docs).

tools/kblib.py

@@ -157,5 +157,4 @@ def open_readonly() -> tuple[ladybug.Database, ladybug.Connection]:
     if not DB_PATH.exists():
         raise FileNotFoundError(f"{DB_PATH} missing - run bin/kb/index first")
     db, conn = connect(read_only=True)
-    init_schema(conn)
     return db, conn