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>

core/schema/localai.go

@@ -208,6 +208,9 @@ type SysInfoModel struct {
 	// when the model has no local process (a distributed worker holds it) or
 	// the process could not be read.
 	Process *SysInfoProcess `json:"process,omitempty"`
+	// SizeVRAM is DRM-accounted resident device memory in bytes. Nil means
+	// the backend process tree has no complete supported reading.
+	SizeVRAM *uint64 `json:"size_vram,omitempty"`
 }
 
 // SysInfoProcess is a point-in-time reading of one backend process.

core/schema/system_info_test.go

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MIT
+package schema_test
+
+import (
+	"encoding/json"
+
+	"github.com/mudler/LocalAI/core/schema"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("SysInfoModel memory", func() {
+	It("omits unavailable VRAM while preserving a measured zero", func() {
+		entry := schema.SysInfoModel{ID: "model"}
+		encoded, err := json.Marshal(entry)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(string(encoded)).To(MatchJSON(`{"id":"model"}`))
+
+		zero := uint64(0)
+		entry.SizeVRAM = &zero
+		encoded, err = json.Marshal(entry)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(string(encoded)).To(MatchJSON(`{"id":"model","size_vram":0}`))
+	})
+})