fix(acms): implement real retrieval logic in all 6 spec-required context strategies

features/context_strategy_registry.feature

@@ -175,11 +175,11 @@ Feature: Context Strategy Registry
     Then "plan-decision-context" can_handle should return 0.7
 
   # ---------------------------------------------------------------------------
-  # Stub assemble (no-op)
+  # Strategy assemble — empty backends return empty fragment lists
   # ---------------------------------------------------------------------------
 
   @strategy_assemble
-  Scenario: Stub strategies return empty fragment lists
+  Scenario: Strategies return empty fragment lists when backends return no data
     Given all built-in strategies are instantiated
     And a BackendSet with all backends
     And a default ContextRequest
@@ -187,6 +187,64 @@ Feature: Context Strategy Registry
     When each strategy assembles with budget 1000
     Then every strategy should return an empty fragment list
 
+  # ---------------------------------------------------------------------------
+  # Strategy assemble — populated backends return non-empty fragment lists
+  # ---------------------------------------------------------------------------
+
+  @strategy_assemble @real_retrieval
+  Scenario: SimpleKeywordStrategy returns fragments from text backend
+    Given all built-in strategies are instantiated
+    And a BackendSet with a populated text backend
+    And a ContextRequest with query "authentication"
+    And a default PlanContext
+    When the "simple-keyword" strategy assembles with budget 10000
+    Then the "simple-keyword" strategy should return at least 1 fragment
+
+  @strategy_assemble @real_retrieval
+  Scenario: SemanticEmbeddingStrategy returns fragments from vector backend
+    Given all built-in strategies are instantiated
+    And a BackendSet with a populated vector backend
+    And a ContextRequest with query "authentication"
+    And a default PlanContext
+    When the "semantic-embedding" strategy assembles with budget 10000
+    Then the "semantic-embedding" strategy should return at least 1 fragment
+
+  @strategy_assemble @real_retrieval
+  Scenario: BreadthDepthNavigatorStrategy returns fragments from graph backend
+    Given all built-in strategies are instantiated
+    And a BackendSet with a populated graph backend
+    And a ContextRequest with focus "uko:class/AuthManager"
+    And a default PlanContext
+    When the "breadth-depth-navigator" strategy assembles with budget 10000
+    Then the "breadth-depth-navigator" strategy should return at least 1 fragment
+
+  @strategy_assemble @real_retrieval
+  Scenario: ARCEStrategy returns fragments from all backends
+    Given all built-in strategies are instantiated
+    And a BackendSet with all populated backends
+    And a ContextRequest with query "authentication"
+    And a default PlanContext
+    When the "arce" strategy assembles with budget 10000
+    Then the "arce" strategy should return at least 1 fragment
+
+  @strategy_assemble @real_retrieval
+  Scenario: TemporalArchaeologyStrategy returns fragments from temporal backend
+    Given all built-in strategies are instantiated
+    And a BackendSet with populated graph and temporal backends
+    And a default ContextRequest
+    And a default PlanContext
+    When the "temporal-archaeology" strategy assembles with budget 10000
+    Then the "temporal-archaeology" strategy should return at least 1 fragment
+
+  @strategy_assemble @real_retrieval
+  Scenario: PlanDecisionContextStrategy returns fragments from temporal backend
+    Given all built-in strategies are instantiated
+    And a BackendSet with a populated temporal backend
+    And a default ContextRequest
+    And a default PlanContext
+    When the "plan-decision-context" strategy assembles with budget 10000
+    Then the "plan-decision-context" strategy should return at least 1 fragment
+
   # ---------------------------------------------------------------------------
   # ContextStrategyResult deterministic ordering
   # ---------------------------------------------------------------------------