fix: show open window indicators for bottom dock tiles

[Pranjal1423]

Closes #378

Description

This PR fixes missing open window indicators (active dots, focused pills, and minimized rings) underneath items placed on the bottom dock (such as WooCommerce ,Marketing, or Payments).

Root Causes & Fixes

1. CSS Clipping:
   • Issue: .desktop-mode-dock__scroll had overflow-y: hidden with 0px bottom padding. Positioned at bottom: -4px, active indicators were rendered outside the scroll wrapper bounds and completely clipped by the browser.
   • Fix: Added padding-bottom: 6px and overflow-y: visible to the scroll and pinned containers in dock.css, and positioned the indicator at bottom: -3px.
2. URL Parameter Encoding Mismatch:
   • Issue: Encoded plugin routes (like wc-admin&path=%2Fmarketing) slugified to admin-php-page-wc-admin-path-2Fmarketing (with 2F), while the opened window URL slugified to admin-php-page-wc-admin-path-marketing. The resulting base ID mismatch prevented the dock from identifying open windows.
   • Fix: Added decodeURIComponent handling inside slugify() in utils.ts so encoded and unencoded URLs slugify identically.
3. Window ID Resolution Fallback:
   • Issue: Windows opened via deep links or native remaps had base IDs that didn't strictly match the dock tile URL's derived ID. Additionally, promoted desktop icons (dock: prefix) carried empty URLs, causing base ID resolution to fail.
   • Fix: Updated resolveItemBaseId() in dock.ts to handle promoted desktop icons and added a fallback matcher to updateActiveStates() checking derived URL IDs and tile IDs.

Verification

• Build: npm run build:desktop built successfully.
• Typecheck: npm run typecheck passed with no errors.
• Lint: npm run lint passed with no errors.
• Unit Tests: npx vitest run tests/vitest/dock-minimized-indicator.test.ts passed 9/9 tests.

Before fix

After fix

[AllTerrainDeveloper]

Went through this today. Nice find on the three root causes, and thanks for the before/after shots, they made it easy to verify. I checked out the branch and ran the full vitest suite (2085 tests), all green, which was my main worry since slugify feeds window ids everywhere. Left a few small comments inline, nothing blocking. Thanks for the contribution!

[AllTerrainDeveloper]

Tested and works nicely, seems I messed up with the review having other changes applied. I will merge the changes and do separate changes later for adding tests.

Thank you again for the fixes!

[AllTerrainDeveloper]

Just a note, that you are already appearing here:
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If you have any inconvenience, please tell it to me :)

[Pranjal1423]

Thank you so much !! :)