[NehonaYa]

When clipboard access is unavailable or denied, copying a report or link fails without giving the user a way to recover. Show the text in a read-only dialog so it can be copied manually, and report success only after the browser completes the copy.

The same fallback is used by the report, published URL, data source URL, and widget SQL copy actions. The dialog selects the text, keeps keyboard focus inside, and clears the text on close.

Fixes #22

Validation:

• Ran the repository checks and all 15 Node tests.
• Built the three application outputs in an isolated Windows workspace using esbuild 0.28.0 and checked the generated JavaScript syntax.
• In Microsoft Edge, checked unavailable and denied clipboard access, focus and Escape behavior, a 320px viewport, and that markup in the copied text is not executed.
• An axe-core scan of the dialog reported no violations; two color contrast checks need manual review. A screen reader pass has not been performed.

[Gabriel Mongefranco (gabrielmongefranco)]

Thank you, NehonaYa ! I'll go ahead and merge this.