fix(sandbox): refetch the entity when the dev server comes up

[pedrofrxncx]

Fixes #3482.

Payoff: the Sections-Editor/Content panel gets permanently stuck on a spinner on a cold-start open of a virtual MCP, requiring a hard page refresh — a first-run experience bug users hit constantly.

Root cause: previewUrl (which gates the CMS/Content panels — see sandbox-lifecycle-context.tsx's vmEntry?.previewUrl) is derived from the virtual MCP entity's sandboxMap, fetched via a useSuspenseQuery with a 60s staleTime and no live-push subscription. SANDBOX_START can resolve, and the SSE lifecycle can reach "running", before the pod has finished writing its previewUrl into that entity's sandboxMap — so on first open, nothing ever re-fetches the entity and previewUrl stays null until the user does a hard refresh (which re-fetches everything from scratch).

Fix: sandbox-events-context.tsx already invalidates the decofile/live-meta queries at the lifecycle.phase === "running" transition (the exact moment the dev server confirms up). This adds one more invalidation at that same point — the virtual-MCP collection-item query (via the existing invalidateVirtualMcpQueries helper) — so the entity refetches and previewUrl picks up the freshly-written sandboxMap entry without a manual reload.

Verify: bun run fmt and cd apps/web && bunx tsc --noEmit both pass. This is a live-SSE reactivity path (EventSource + entity cache) that isn't cheaply unit-testable without mocks the repo's testing rules disallow for the unit tier — full CI/e2e validates the rest; a reviewer can confirm by opening a virtual MCP from a cold start and immediately switching to the Content/CMS tab (repro steps in #3482) and observing it now self-heals instead of requiring a refresh.

Diff: +8/-1, one file, one concern.

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Summary by cubic

Fixes a cold-start race that left the Sections-Editor/Content panel stuck on a spinner. When the dev server reports “running,” we now refetch the virtual MCP entity so previewUrl updates without a hard refresh.

• Bug Fixes
  • On lifecycle.phase === "running", call invalidateVirtualMcpQueries to re-fetch the virtual MCP collection-item query and pick up the sandboxMap previewUrl.

^{Written for commit 23955cd. Summary will update on new commits.}