fix(spec-004): Use documented CRUD on /assignments instead of undocumented /assign

Changes:
- Replace POST /assign with standard CRUD operations
- Restore strategy: DELETE existing + POST new assignments
- Graph Contract: assignments_create/update/delete_path + methods
- Handle 201 Created (POST) and 204 No Content (DELETE)
- Fail-soft: continue if individual assignment fails

Based on: Microsoft Learn Graph API docs + real-world usage patterns

specs/004-assignments-scope-tags/spec.md

@@ -183,12 +183,18 @@ ### Restore with Group Mapping
 **FR-004.11**: System MUST persist group mapping selections in RestoreRun metadata for audit and rerun purposes.
 
 **FR-004.12**: When restoring assignments, system MUST:
-1. Replace source group IDs with mapped target group IDs
-2. Skip assignments marked "Skip"
+1. Replace source group IDs with mapped target group IDs in assignment objects
+2. Skip assignments marked "Skip" in group mapping
 3. Preserve include/exclude intent and filters
-4. Call POST `/deviceManagement/configurationPolicies/{id}/assign` (not PATCH) with complete mapped assignments array (replaces all assignments atomically)
-5. Handle 204 No Content or 200 OK as success
-6. Log Graph request-id and client-request-id on failure
+4. Execute restore via DELETE-then-CREATE pattern:
+   - Step 1: GET existing assignments from target policy
+   - Step 2: DELETE each existing assignment (via DELETE `/assignments/{id}`)
+   - Step 3: POST each new/mapped assignment (via POST `/assignments`)
+5. Handle failures gracefully:
+   - 204 No Content on DELETE = success
+   - 201 Created on POST = success
+   - Log request-id/client-request-id on any failure
+6. Continue with remaining assignments if one fails (fail-soft)
 
 **FR-004.13**: System MUST handle assignment restore failures gracefully:
 - Log per-assignment outcome (success/skip/failure)
@@ -274,25 +280,30 @@ ### Endpoints to Add (Production-Tested Strategies)
      - Client-side filter to extract assignments
    - **Reason**: Known Graph API quirks with assignment expansion on certain template families
 
-2. **POST** `/deviceManagement/configurationPolicies/{id}/assign` (POST only, NOT PATCH)
-   - Body: `{ assignments: [assignment objects] }`
-   - Returns: 204 No Content or 200 OK
-   - **Note**: This is an action endpoint, replaces entire assignments array
-   - Example payload:
-     ```json
-     {
-       "assignments": [
-         {
-           "id": "00000000-0000-0000-0000-000000000000",
-           "target": {
-             "@odata.type": "#microsoft.graph.groupAssignmentTarget",
-             "groupId": "abc-123-def"
-           },
-           "intent": "apply"
-         }
-       ]
-     }
-     ```
+2. **Assignment CRUD Operations** (Standard Graph Pattern)
+   
+   - **POST** `/deviceManagement/configurationPolicies/{id}/assignments`
+     - Body: Single assignment object
+     - Returns: 201 Created with assignment object
+     - Example:
+       ```json
+       {
+         "target": {
+           "@odata.type": "#microsoft.graph.groupAssignmentTarget",
+           "groupId": "abc-123-def"
+         },
+         "intent": "apply"
+       }
+       ```
+   
+   - **PATCH** `/deviceManagement/configurationPolicies/{id}/assignments/{assignmentId}`
+     - Body: Assignment object (partial update)
+     - Returns: 200 OK with updated assignment
+   
+   - **DELETE** `/deviceManagement/configurationPolicies/{id}/assignments/{assignmentId}`
+     - Returns: 204 No Content
+   
+   - **Restore Strategy**: DELETE all existing assignments, then POST new ones (atomic via transaction pattern)
 
 3. **POST** `/directoryObjects/getByIds` (Stable Group Resolution)
    - Body: `{ "ids": ["id1", "id2"], "types": ["group"] }`
@@ -316,11 +327,20 @@ ### Graph Contract Updates
 
 ```php
 'settingsCatalogPolicy' => [
-    // ... existing
-    'assignments_path' => '/deviceManagement/configurationPolicies/{id}/assignments',
-    'assign_method' => 'POST',
-    'assign_path' => '/deviceManagement/configurationPolicies/{id}/assign',
+    // ... existing config
+    
+    // Assignments CRUD (standard Graph pattern)
+    'assignments_list_path' => '/deviceManagement/configurationPolicies/{id}/assignments',
+    'assignments_create_path' => '/deviceManagement/configurationPolicies/{id}/assignments',
+    'assignments_create_method' => 'POST',
+    'assignments_update_path' => '/deviceManagement/configurationPolicies/{id}/assignments/{assignmentId}',
+    'assignments_update_method' => 'PATCH',
+    'assignments_delete_path' => '/deviceManagement/configurationPolicies/{id}/assignments/{assignmentId}',
+    'assignments_delete_method' => 'DELETE',
+    
+    // Scope Tags
     'supports_scope_tags' => true,
+    'scope_tag_field' => 'roleScopeTagIds', // array in policy payload
 ],
 ```