chore(repo): canonicalize — add .core/go.yaml + scope .gitignore to runtime subdirs

The .core/ root holds tracked Lethean canon config (go.yaml, build.yaml,
agents.yaml, etc.). Only the runtime subdirs (workspace/, vm/, cache/,
runtime/) and per-repo runtime artifacts should be gitignored.

Brings this repo into the managed canonical set per audit-sweep
discovery filter.

Co-Authored-By: Cladius Maximus <cladius@lethean.io>

.core/go.yaml

@@ -0,0 +1,13 @@
+# .core/go.yaml — Go subtree marker for the Lethean canon.
+# Presence of .core/ + go/ marks this repo as a managed canonical repo.
+# Audit-sweep + dispatch tooling discover via this marker.
+version: 1
+
+project:
+  name: docs
+  type: go
+
+go:
+  module: dappco.re/go/core/docs
+  subtree: go
+  go_version: "1.26.0"

.gitignore

@@ -1,5 +1,10 @@
 site/
 .cache/
 .DS_Store
-.core/
 .idea/
+.core/workspace/
+.core/vm/
+.core/cache/
+.core/runtime/
+.core/*.duckdb*
+.core/coderabbit-findings.txt