v0.3.0 finish: TUI tests, embedding wiring, gateway :configured, focus commands, export cleanup

- TUI: Fix stale contract (remove handle-return/*incoming-msgs*), rewrite
  10->13 tests (38 checks, 100% pass). Export missing symbols from TUI
  package. Fix view-chat contract arity.
- Gateway messaging: Add :configured key to registry (boolean, nil default).
  Fix contract to match (vault-based, not env-var-based).
- Async Embedding Gateway: Add *embedding-backend* var, embeddings-compute
  function. Modify ingest-ast to populate vectors on new objects.
  Add EMBEDDING_PROVIDER env var support. Add Contract + 4 tests (8 checks).
- Context Manager: Add /focus, /scope, /unfocus commands to TUI on-key
  handler. Commands degrade gracefully when context-manager not loaded.
- Export hygiene: Remove 30+ ghost exports (undefined symbols). Remove
  duplicate/mismatched names. Exports now match actual definitions.

org/system-model-embedding.org

@@ -88,9 +88,16 @@ This replaces the old ~system-embedding-gateway~ with the same logic but renamed
 
 ** Object embedding and queuing
 #+begin_src lisp
+(defvar *embedding-backend* nil
+  "Explicit backend override (nil = use *embedding-provider*).")
+
+(defun embeddings-compute (text)
+  "Compute an embedding vector for text using the active backend."
+  (embed-object text))
+
 (defun embed-object (text)
   "Embed a single text string using the active backend."
-  (let* ((selected (or *embedding-provider* :hashing))
+  (let* ((selected (or *embedding-backend* *embedding-provider* :hashing))
          (backend (case selected
                     (:local #'embedding-backend-local)
                     (:openai #'embedding-backend-openai)
@@ -109,15 +116,80 @@ This replaces the old ~system-embedding-gateway~ with the same logic but renamed
   (log-message "EMBEDDING: Queued object"))
 
 (defun embed-all-pending ()
-  "Drain the embedding queue, batch-process all queued objects."
+  "Drain the embedding queue, store vectors in the store-keyed objects."
   (let ((batch (nreverse *embedding-queue*)))
     (setf *embedding-queue* nil)
     (dolist (item batch)
       (handler-case
-          (let ((text (if (stringp item) item (format nil "~a" item))))
-            (embed-object text))
+          (let ((id (getf item :id))
+                (text (getf item :text)))
+            (when (and id text)
+              (let ((vec (embeddings-compute text))
+                    (obj (gethash id *memory-store*)))
+                (when (and obj vec (not (listp vec)))
+                  (setf (memory-object-vector obj) vec))
+                (log-message "EMBEDDING: Computed vector for ~a (~d dims)" id (length vec)))))
         (error (c)
           (log-message "EMBEDDING: Failed to embed object: ~a" c))))))
 
+;; Apply env var override at load time
+(let ((provider-env (uiop:getenv "EMBEDDING_PROVIDER")))
+  (when provider-env
+    (let ((kw (intern (string-upcase provider-env) :keyword)))
+      (setf *embedding-provider* kw)
+      (log-message "EMBEDDING: Set provider to ~a from EMBEDDING_PROVIDER env" kw))))
+
 (log-message "EMBEDDING: Gateway loaded with provider ~a" *embedding-provider*)
 #+end_src
+
+* Contract
+
+1. (embeddings-compute text): produces a vector (single-float array) for
+   any text string using the active backend (~*embedding-backend*~ or
+   ~*embedding-provider*~).
+2. (embedding-backend-hashing text): zero-dependency fallback. Returns
+   an 8-element single-float vector deterministically from SHA-256.
+3. (embed-all-pending): drains ~*embedding-queue*~, computes vectors for
+   all queued objects, and stores them in ~*memory-store*~ entries.
+
+* Test Suite
+#+begin_src lisp
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (ql:quickload :fiveam :silent t))
+
+(defpackage :passepartout-embedding-tests
+  (:use :cl :passepartout)
+  (:export #:embedding-suite))
+
+(in-package :passepartout-embedding-tests)
+
+(fiveam:def-suite embedding-suite :description "Embedding gateway verification")
+(fiveam:in-suite embedding-suite)
+
+(fiveam:test test-embedding-backend-hashing
+  "Contract 2: hashing backend produces 8-element float vector."
+  (let ((vec (embedding-backend-hashing "hello world")))
+    (fiveam:is (arrayp vec))
+    (fiveam:is (= 8 (length vec)))
+    (fiveam:is (every #'numberp (coerce vec 'list)))))
+
+(fiveam:test test-embedding-backend-hashing-deterministic
+  "Contract 2: same input produces same vector."
+  (let ((v1 (embedding-backend-hashing "test"))
+        (v2 (embedding-backend-hashing "test")))
+    (fiveam:is (equalp v1 v2))))
+
+(fiveam:test test-embeddings-compute
+  "Contract 1: embeddings-compute returns a float vector."
+  (let ((vec (embeddings-compute "some text")))
+    (fiveam:is (arrayp vec))
+    (fiveam:is (> (length vec) 0))))
+
+(fiveam:test test-embed-queue-and-drain
+  "Contract 3: embed-all-pending drains queue and stores vectors."
+  (let ((*embedding-queue* nil))
+    (embed-queue-object '(:id "test-obj" :text "sample text"))
+    (fiveam:is (= 1 (length *embedding-queue*)))
+    (embed-all-pending)
+    (fiveam:is (null *embedding-queue*))))
+#+end_src