Fix the analysis re-run button silently doing nothing

[skerbis]

Summary

Stacked on #1062 (toolbar hardening) — please review/merge that one first.

The button's click handler was only ever bound from a DOMContentLoaded listener. A script added via rex_view::addJsFile() can finish loading/executing after that event already fired (common on a backend page with many other scripts), in which case the listener never runs at all - no handler ever gets bound, and the link's href="#" just does nothing on click, which is exactly what was being observed.

Fixed the same way this project's own ai-chat-warm-cache.js already does it: try a jQuery rex:ready listener (also covers REDAXO's own AJAX-driven content swaps), fall back to DOMContentLoaded, and call init() unconditionally as well to cover the case where the DOM is already ready by the time this script runs. init() now guards against running its setup more than once per page load (a dataset flag on the app root), since it can legitimately fire from multiple triggers now.

Also moved the script registration from pages/analysis.php into boot.php, gated to this subpage specifically - matches this addon's own existing confetti.min.js pattern instead of introducing a second, different way of loading a JS file for the same page.

Test plan

• Verified the click handler binds and fires correctly regardless of load timing (tested the "script loads after DOMContentLoaded" race specifically).
• php -l + PHPStan on the changed files: 0 findings.

🤖 Generated with Claude Code

[skerbis]

Closing as part of flattening the stack into independent PRs — this and #1062/#1064 are being combined into one PR ("Harden, fix and animate the analysis re-run trigger"), based on #1067 instead of chained serially. Will link the replacement here once opened.

[skerbis]

Combined into #1068.