fix(desktop): use a managed headless Ollama runtime

INSTALLATION_GUIDE.md

@@ -318,21 +318,24 @@ and sharing behavior.
 VidXP search does not require a language model. To let CLI, HTTP, or MCP
 queries plan searches and draft grounded answers locally, enable **Local
 grounded answers** in VidXP Desktop setup. Desktop checks for a compatible
-loopback Ollama service, asks before installing Ollama through the supported
-Windows or macOS package manager when needed, and explicitly downloads the
-approved Qwen3.5 4B model. Linux setup links to Ollama's official installation
-instructions instead of running a privileged script.
+loopback Ollama service and then for an existing Ollama executable. When neither
+is available on Windows x86-64 or macOS Apple Silicon, Desktop asks before
+downloading a pinned, checksum-verified headless runtime into VidXP's private
+data. It does not install the Ollama desktop app. Linux setup links to Ollama's
+official installation instructions instead of running a privileged script.
 
 This optional feature follows Ollama's platform floor: Windows 10 22H2 or
 newer, or macOS 14 or newer. VidXP Desktop itself can still run without local
 grounded answers on older supported systems.
 
-The model is an additional approximately 3.4 GB download and has no per-run
-API charge or numbered hosted-model allowance. It uses local storage, memory,
-compute time, and electricity. Desktop configures the private service address
-for its browser, worker, API, Premiere, and generated MCP/Codex setup; there is
-no URL field to fill in. A command-line-only installation remains available
-for developers and custom deployments.
+The model is an additional approximately 3.4 GB download. When Desktop must
+provide the headless runtime, that download is up to approximately 1.36 GiB;
+reusing Ollama avoids it. Local answers have no per-run API charge or numbered
+hosted-model allowance, but they use local storage, memory, compute time, and
+electricity. Desktop configures the private service address for its browser,
+worker, API, Premiere, and generated MCP/Codex setup; there is no URL field to
+fill in. A command-line-only installation remains available for developers and
+custom deployments.
 
 The complete setup and its current evidence limitations are documented under
 [Enable local grounded answers](docs/local-api.md#enable-local-grounded-answers).

benchmarks/codex-mcp/.npmrc

@@ -1 +1,2 @@
 engine-strict=true
+omit=optional

desktop/about.toml

@@ -3,6 +3,7 @@ accepted = [
   "MIT",
   "BSD-2-Clause",
   "BSD-3-Clause",
+  "CDLA-Permissive-2.0",
   "ISC",
   "MPL-2.0",
   "Unicode-3.0",

desktop/runtime-manifest.json

@@ -11,8 +11,28 @@
     "engine": "ollama",
     "model": "qwen3.5:4b-q4_K_M",
     "download_size_bytes": 3650722202,
+    "managed_runtime": {
+      "version": "0.32.5",
+      "maximum_download_size_bytes": 1457824795,
+      "artifacts": {
+        "windows-x86_64": {
+          "url": "https://github.com/ollama/ollama/releases/download/v0.32.5/ollama-windows-amd64.zip",
+          "sha256": "7c941ae084569d298062d29f8139163a3187c76dbca0479c70d085e78fd8c7bb",
+          "download_size_bytes": 1457824795,
+          "archive": "zip",
+          "executable": "ollama.exe"
+        },
+        "macos-aarch64": {
+          "url": "https://github.com/ollama/ollama/releases/download/v0.32.5/ollama-darwin.tgz",
+          "sha256": "5789dd037a86adb328c72c11fc45e6c558452d07e5b50814a8bdb7b0fbdbcd81",
+          "download_size_bytes": 145747028,
+          "archive": "tar_gz",
+          "executable": "ollama"
+        }
+      }
+    },
     "label": "Local grounded answers",
-    "description": "Turn VidXP search evidence into cited answers on this computer. Setup reuses or installs Ollama and downloads the approved Qwen 3.5 4B model."
+    "description": "Turn VidXP search evidence into cited answers on this computer. Setup reuses Ollama when available or downloads a private headless runtime and the approved Qwen 3.5 4B model."
   },
   "surfaces": {
     "worker": {