feat(window): add window lifecycle and launch endpoints

docs/API.md

@@ -194,6 +194,89 @@ Move only:
 }
 ```
 
+## `GET /windows`
+
+List desktop windows using structured filters instead of shelling out.
+
+Query params:
+
+- `title_contains` (optional substring match)
+- `title_regex` (optional case-insensitive regex)
+- `process_name` (optional exact process name, e.g. `explorer.exe`)
+- `hwnd` (optional exact window handle)
+- `visible_only` (bool, default `true`)
+
+```json
+{
+  "ok": true,
+  "count": 1,
+  "windows": [
+    {
+      "hwnd": 132640,
+      "title": "WinDirStat",
+      "class_name": "WinDirStatMainWindow",
+      "pid": 18420,
+      "process_name": "windirstat.exe",
+      "visible": true,
+      "enabled": true,
+      "minimized": false,
+      "maximized": false,
+      "foreground": true,
+      "rect": {"x": 194, "y": 116, "width": 1532, "height": 870}
+    }
+  ]
+}
+```
+
+Notes:
+- Currently supported on Windows hosts only.
+- Returns `409` for ambiguous write-target matches when a mutation endpoint would affect multiple windows.
+
+## `POST /windows/action`
+
+Perform a structured window action against exactly one matched window.
+
+```json
+{
+  "action": "focus",
+  "title_contains": "WinDirStat",
+  "visible_only": true,
+  "timeout_ms": 3000
+}
+```
+
+Supported actions:
+- `focus`
+- `restore`
+- `minimize`
+- `maximize`
+- `close`
+
+The response includes the matched pre-action window and the final observed window state (or `closed=true` if it disappeared).
+
+## `POST /launch`
+
+Start an app/process without invoking a shell.
+
+```json
+{
+  "executable": "C:/Program Files/WinDirStat/WinDirStat.exe",
+  "args": [],
+  "cwd": "C:/Program Files/WinDirStat",
+  "wait_for_window": true,
+  "match": {
+    "title_contains": "WinDirStat",
+    "visible_only": true
+  },
+  "timeout_ms": 8000
+}
+```
+
+Notes:
+- Launch uses direct process execution (`subprocess.Popen`) rather than PowerShell/CMD.
+- If `wait_for_window=true`, the server polls for a matching window and returns `window_found`.
+- `dry_run=true` returns the resolved argv/cwd without launching.
+
 ## `POST /ocr`
 
 Extract visible text from either a full screenshot, a region crop, or caller-provided image bytes.