[Souvenirser]

Large valid JSON could leave the result pane blank because the page called Formatter before enabling result actions. The large JSON text view renders synchronously and was rejected by the existing rendering guard. Initialize the successful result state before formatting, and clear and hide the previous text view when showing a placeholder or error.

Validation:

• 270 tests pass, including seven page-rendering regression cases.
• Chrome extension build succeeds.
• The original 1.55 MB sample displays all 2,796,387 formatted characters in the built page; parsed values and the final data match the original. Clearing the input and returning to small JSON work.
• ESLint diagnostics match the existing baseline: 10 errors and 21 warnings, with none added.
• Installed Chrome extension behavior and clipboard/download completeness still need verification; browser control and in-app browser interfaces prevented those checks.

No dependency changes or original sample data are included.