feat: add confirmed Take down stack action with optional volume removal (#1599)

* feat: add confirmed Take down stack action with optional volume removal

Expose Take down in the stack header and sidebar with a confirmation dialog
that runs compose down while keeping the stack definition on disk. Optional
volume removal is gated by node capability and stack:deploy permission, with
remote gateway preflight before proxying removeVolumes requests.

Closes #1582

* fix: reset take-down volume checkbox when dialog closes

* test: align getStackMenuVisibility assertions with showTakeDown key

getStackMenuVisibility now returns a fifth lifecycle flag, showTakeDown,
but three exhaustive toEqual assertions still listed only the prior four
keys and failed. Add the expected showTakeDown value to each: true for
the partial and exited running-stack cases, false for the self stack.

* test: cover Take down visibility for running non-self stacks

The getStackMenuVisibility assertions exercised the partial and exited
branches and the self-stack guard, but not the raw === 'running' literal
that drives showTakeDown for a normal running stack. Add a case so a
regression dropping 'running' from that check is caught.

* fix: drop Take down from header overflow and wire activity shortcut

Remove duplicate Take down from More actions.

Keep inline button when running, sidebar menu, and Cmd+ArrowDown.

Record stack_taken_down in activity on successful POST /down.

frontend/src/components/EditorLayout/editor-view-blocks.tsx

@@ -16,6 +16,7 @@ import {
     ArrowUpRight,
     Copy,
     CloudDownload,
+    ArrowDownToLine,
     Layers,
     List,
     Maximize2,
@@ -133,6 +134,8 @@ export interface StackIdentityHeaderProps {
     rollbackStack: () => Promise<void>;
     scanStackConfig: () => Promise<void>;
     requestDeleteStack: () => void;
+    requestTakeDownStack: (stackName: string) => void;
+    showTakeDown: boolean;
     /** True when this stack is the running Sencho instance on the active node. */
     isSelfStack?: boolean;
     stackMuteActions?: ReturnType<typeof useStackMuteActions>;
@@ -158,6 +161,8 @@ export function StackIdentityHeader({
     rollbackStack,
     scanStackConfig,
     requestDeleteStack,
+    requestTakeDownStack,
+    showTakeDown,
     isSelfStack = false,
     stackMuteActions,
 }: StackIdentityHeaderProps) {
@@ -219,6 +224,20 @@ export function StackIdentityHeader({
                                         {loadingAction === 'stop' ? 'Stopping...' : 'Stop'}
                                     </Button>
                                 )}
+                                {isRunning && showTakeDown && (
+                                    <Button
+                                        type="button"
+                                        size="sm"
+                                        variant="outline"
+                                        data-testid="stack-take-down-button"
+                                        className="rounded-lg max-md:h-11 border-warning/40 text-warning hover:bg-warning/10"
+                                        onClick={() => requestTakeDownStack(stackName)}
+                                        disabled={loadingAction !== null || selfProtected}
+                                    >
+                                        <ArrowDownToLine className="w-4 h-4 mr-2" strokeWidth={1.5} />
+                                        {loadingAction === 'down' ? 'Taking down...' : 'Take down'}
+                                    </Button>
+                                )}
                                 <Button type="button" size="sm" variant="outline" className="rounded-lg max-md:h-11" onClick={updateStack} disabled={loadingAction !== null || selfProtected}>
                                     <CloudDownload className="w-4 h-4 mr-2" strokeWidth={1.5} />
                                     {loadingAction === 'update' ? 'Updating...' : 'Update'}