[Frontends] Reduce WebContainer/StackBlitz startup noise

[mkucmus]

Part of epic #2360.

Reduce WebContainer- and StackBlitz-specific noise during first boot so the terminal does not look like the environment is "figuring itself out live."

Scope

• Identify sources of repeated WASM / OXC binding downloads (likely rolldown / oxc-parser duplicate versions); deduplicate via pnpm overrides or resolutions
• Suppress the WASI experimental warning via NODE_OPTIONS="--no-warnings=ExperimentalWarning" configured in the StackBlitz env
• Hide the Nuxt startup banner and QR code (NUXT_TELEMETRY_DISABLED, adjust nuxt.config)
• Configure .stackblitzrc / stackblitz.config to collapse the terminal by default and prioritize the preview pane
• Verify fixes in a fresh incognito StackBlitz session to avoid cached state

Acceptance criteria

• No duplicate WASM/OXC binding downloads during first boot
• WASI experimental warning no longer appears in the default terminal output
• Nuxt banner and QR code are suppressed in the StackBlitz context
• Preview pane is foregrounded over the terminal on first open
• Verified in a fresh incognito session

[mdanilowicz]

oxc-* errors will be fixed with the bump nuxt version