feat: block self-stack lifecycle ops with UI and preflight guardrails (#1569)

* feat: block self-stack lifecycle ops with UI and preflight guardrails

Refuse update, deploy, down, stop, and delete when the stack matches Sencho's compose project.

Return 409 self_stack_protected. Expose isSelf on /statuses and disable guarded UI actions.

Add SelfStackProtectedDialog and self-managed-stack preflight warning.

Closes #1564

* fix: add missing stackSelfFlags mock to useSidebarContextMenu test

The production hook now reads stackListState.stackSelfFlags[file], but the
test mock did not include it, causing 6 tests to fail with TypeError:
Cannot read properties of undefined (reading 'web.yml').

* fix: harden self-stack protection during startup

Add a global environment preflight warning when Sencho is managed inside COMPOSE_DIR.

Align status decoration and route guards on Docker label fallback detection.

Block rollback and service-level stop on the protected self stack.

* fix: add self_stack_location to diagnostics-route expected check IDs

frontend/src/components/EditorLayout/MobileStackDetail.tsx

@@ -70,6 +70,7 @@ export function MobileStackDetail(props: EditorViewProps) {
         setGitSourceOpen,
         setCopiedDigest,
         requestDeleteStack,
+        isSelfStack = false,
         onMobileBack,
         onCloseEditor,
         hasUnsavedChanges,
@@ -153,6 +154,7 @@ export function MobileStackDetail(props: EditorViewProps) {
                         rollbackStack={rollbackStack}
                         scanStackConfig={scanStackConfig}
                         requestDeleteStack={requestDeleteStack}
+                        isSelfStack={isSelfStack}
                         stackMuteActions={stackMuteActions}
                     />
                 </div>