feat(ui): add chat-driven dataset review flow

Move dataset review clarification into the assistant workspace and
rework the review page into a chat-centric layout with execution rails.

Add session-scoped assistant actions for mappings, semantic fields,
and SQL preview generation. Introduce optimistic locking for dataset
review mutations, propagate session versions through API responses,
and mask imported filter values before assistant exposure.

Refresh tests, i18n, and spec artifacts to match the new workflow.

BREAKING CHANGE: dataset review mutation endpoints now require the
X-Session-Version header, and clarification is no longer handled
through ClarificationDialog-based flows

specs/027-dataset-llm-orchestration/contracts/api.yaml

@@ -12,8 +12,8 @@ tags:
   - name: Mapping Review
   - name: Preview and Launch
   - name: Exports
+  - name: Assistant Integration
 
-paths:
 security:
   - bearerAuth: []
 
@@ -85,6 +85,7 @@ paths:
       summary: Update resumable session lifecycle state
       parameters:
         - $ref: '#/components/parameters/SessionId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       requestBody:
         required: true
         content:
@@ -129,6 +130,7 @@ paths:
       summary: Apply a semantic source to the current session
       parameters:
         - $ref: '#/components/parameters/SessionId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       requestBody:
         required: true
         content:
@@ -156,6 +158,7 @@ paths:
       parameters:
         - $ref: '#/components/parameters/SessionId'
         - $ref: '#/components/parameters/FieldId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       requestBody:
         required: true
         content:
@@ -183,6 +186,7 @@ paths:
       parameters:
         - $ref: '#/components/parameters/SessionId'
         - $ref: '#/components/parameters/FieldId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       responses:
         '200':
           description: Field locked
@@ -202,6 +206,7 @@ paths:
       parameters:
         - $ref: '#/components/parameters/SessionId'
         - $ref: '#/components/parameters/FieldId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       responses:
         '200':
           description: Field unlocked
@@ -236,6 +241,7 @@ paths:
       summary: Submit an answer to the current clarification question
       parameters:
         - $ref: '#/components/parameters/SessionId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       requestBody:
         required: true
         content:
@@ -262,6 +268,7 @@ paths:
       summary: Resume or start clarification mode for the next unresolved question
       parameters:
         - $ref: '#/components/parameters/SessionId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       responses:
         '200':
           description: Clarification resumed
@@ -295,6 +302,7 @@ paths:
       parameters:
         - $ref: '#/components/parameters/SessionId'
         - $ref: '#/components/parameters/MappingId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       requestBody:
         required: true
         content:
@@ -320,6 +328,7 @@ paths:
       parameters:
         - $ref: '#/components/parameters/SessionId'
         - $ref: '#/components/parameters/MappingId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       requestBody:
         required: false
         content:
@@ -344,6 +353,7 @@ paths:
       summary: Trigger Superset-side SQL compilation preview
       parameters:
         - $ref: '#/components/parameters/SessionId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       responses:
         '202':
           description: Preview generation started
@@ -373,6 +383,7 @@ paths:
       x-required-permissions: [dataset:execution:launch]
       parameters:
         - $ref: '#/components/parameters/SessionId'
+        - $ref: '#/components/parameters/SessionVersionHeader'
       responses:
         '201':
           description: Dataset launched
@@ -480,6 +491,14 @@ components:
         minimum: 1
         maximum: 100
         default: 20
+    SessionVersionHeader:
+      name: X-Session-Version
+      in: header
+      required: true
+      description: Optimistic-lock version of the current dataset review session. Requests with a stale version are rejected with conflict semantics.
+      schema:
+        type: integer
+        minimum: 0
 
   securitySchemes:
     bearerAuth:
@@ -586,6 +605,7 @@ components:
       type: object
       required:
         - session_id
+        - version
         - dataset_ref
         - environment_id
         - readiness_state
@@ -597,6 +617,9 @@ components:
       properties:
         session_id:
           type: string
+        version:
+          type: integer
+          minimum: 0
         dataset_ref:
           type: string
         dataset_id:
@@ -991,6 +1014,9 @@ components:
           type: string
           nullable: true
         raw_value: {}
+        raw_value_masked:
+          type: boolean
+          description: Indicates whether the raw filter value has been masked or redacted before exposure to assistant or LLM-facing context.
         normalized_value:
           nullable: true
         source:
@@ -1209,10 +1235,10 @@ components:
 
     ClarificationState:
       type: object
-      required: [clarification_session]
       properties:
         clarification_session:
           $ref: '#/components/schemas/ClarificationSessionSummary'
+          nullable: true
         current_question:
           $ref: '#/components/schemas/ClarificationQuestion'
           nullable: true
@@ -1398,6 +1424,7 @@ components:
       type: object
       required:
         - session
+        - session_version
         - profile
         - findings
         - semantic_sources
@@ -1408,6 +1435,10 @@ components:
       properties:
         session:
           $ref: '#/components/schemas/SessionSummary'
+        session_version:
+          type: integer
+          minimum: 0
+          description: Convenience mirror of the current session version for assistant and workspace synchronization.
         profile:
           $ref: '#/components/schemas/DatasetProfile'
         findings:
@@ -1444,6 +1475,24 @@ components:
           $ref: '#/components/schemas/DatasetRunContextSummary'
           nullable: true
 
+    AssistantMessageRequest:
+      type: object
+      required: [message]
+      description: Request payload accepted by the global Assistant API when the assistant is scoped to dataset review context.
+      properties:
+        conversation_id:
+          type: string
+          nullable: true
+        message:
+          type: string
+          minLength: 1
+          maxLength: 4000
+        dataset_review_session_id:
+          type: string
+          nullable: true
+          description: Optional active dataset review session binding used to ground assistant answers and route approved commands into the current orchestration session.
+      additionalProperties: false
+
     ErrorResponse:
       type: object
       required: [error_code, message]
@@ -1476,4 +1525,4 @@ components:
         errors:
           type: array
           items:
-            $ref: '#/components/schemas/ValidationErrorItem'
+            $ref: '#/components/schemas/ValidationErrorItem'