feat(system): report per-model DRM VRAM (#12026)

* feat(system): report per-model DRM VRAM

Expose optional resident device memory for local backend process trees.
Deduplicate DRM clients and omit unsupported or incomplete readings.
Document accounting limits and preserve a measured zero in JSON.

Closes #11970.

Assisted-by: Codex:gpt-6

* fix(system): document trusted procfs reads

Scope G304 annotations to paths built from the fixed procfs root,
integer process IDs, and kernel directory entries. These reads accept
no user-controlled path components.

Assisted-by: Codex:GPT-6 gosec

---------

Co-authored-by: localai-org-maint-bot <306269227+localai-org-maint-bot@users.noreply.github.com>

swagger/docs.go

@@ -7810,6 +7810,10 @@ const docTemplate = `{
                 },
                 "id": {
                     "type": "string"
+                },
+                "size_vram": {
+                    "description": "SizeVRAM is DRM-accounted resident device memory in bytes. Nil means\nthe backend process tree has no complete supported reading.",
+                    "type": "integer"
                 }
             }
         },

swagger/swagger.json

@@ -7807,6 +7807,10 @@
                 },
                 "id": {
                     "type": "string"
+                },
+                "size_vram": {
+                    "description": "SizeVRAM is DRM-accounted resident device memory in bytes. Nil means\nthe backend process tree has no complete supported reading.",
+                    "type": "integer"
                 }
             }
         },

swagger/swagger.yaml

@@ -2654,6 +2654,11 @@ definitions:
         type: string
       id:
         type: string
+      size_vram:
+        description: |-
+          SizeVRAM is DRM-accounted resident device memory in bytes. Nil means
+          the backend process tree has no complete supported reading.
+        type: integer
     type: object
   schema.SystemInformationResponse:
     properties: