Modularize aird/static/js/share/app.js

[blinkerbit]

Source: gitlab-issues-export.md (Issue 8)

Weight: 5

Problem / context

share/app.js is very large (~2.5k lines), raising cognitive load and SonarJS complexity warnings.

Suggested approach / acceptance criteria

• Split into focused modules (state, API, UI widgets) behind existing entry or build step; preserve behavior.
• Run npm run lint:js; no functional regressions on share flows.