Fix obfuscation toggle for Monarch's icon-only sidebar

[mattebad]

Summary

• keep the obfuscation toggle anchored inside Monarch's new icon-only navigation rail
• rank candidate navigation containers by distinct route density so dashboard widget links cannot capture the toggle
• detect collapsed icon-only navigation and expose accurate accessible toggle state
• support Monarch's current /budget route while retaining legacy /plan
• prevent chart and input masking from leaking onto unsupported routes
• update live smoke, visual capture, snapshot refresh, and user documentation for current routes

Root cause

The sidebar injector discarded navigation links with no text content. Monarch's new sidebar renders icon-only links, so the injector fell back to document-wide link discovery. Duplicate links in dashboard content then caused a broad dashboard ancestor to win, which placed the toggle in the upper-right content header.

Validation

• npm test — 12 tests passed
• node --check MonarchMoneyObfuscate.user.js
• git diff --check
• verified manually in authenticated Monarch via Tampermonkey by the reporter

The regression suite now includes an icon-only rail with competing dashboard links, current budget-route scanning, and unsupported-route auxiliary-mask coverage.