feat: memory scope segmentation — wire context scope into perceive gate

Adds *scope-resolver* hook in core-loop-perceive that the context-manager
skill sets at load time. The perceive gate now passes the active scope
to ingest-ast, tagging all ingested objects with the current context scope.

Implementation:
- core-loop-perceive: *scope-resolver* defvar (default nil → :memex),
  two ingest-ast calls now pass (if *scope-resolver* (funcall it) :memex)
- core-defpackage: export *scope-resolver* and context-query
- system-context-manager: auto-init sets *scope-resolver* to #'current-scope

This completes the Memory Scope Segmentation feature: all three scopes
(:memex, :session, :project) are supported, scope-aware retrieval
(context-query :scope / context-scoped-query) was already implemented,
and ingested objects now correctly carry the active scope.

lisp/core-defpackage.lisp

@@ -51,11 +51,12 @@
    #:context-get-recent-completed-tasks
    #:context-list-all-skills
    #:context-get-skill-source
-   #:context-get-system-logs
-   #:context-resolve-path
-   #:context-get-skill-telemetry
-   #:telemetry-track
-   #:context-assemble-global-awareness
+    #:context-get-system-logs
+    #:context-resolve-path
+    #:context-get-skill-telemetry
+    #:telemetry-track
+    #:context-assemble-global-awareness
+    #:context-query
    #:process-signal
    #:loop-process
    #:perceive-gate
@@ -75,12 +76,13 @@
    #:dispatch-action
    #:register-actuator
    #:load-skill-from-org
-   #:skill-initialize-all
-   #:load-skill-with-timeout
-   #:topological-sort-skills
-   #:validate-lisp-syntax
-   #:defskill
-   #:*skill-registry*
+    #:skill-initialize-all
+    #:load-skill-with-timeout
+    #:topological-sort-skills
+    #:validate-lisp-syntax
+    #:defskill
+    #:*skill-registry*
+    #:*scope-resolver*
    #:skill
    #:skill-name
    #:skill-priority