fix(web): name plugin item actions

[lyzno1]

Summary

• Give the plugin item Check for updates, Plugin info, and Delete icon buttons explicit accessible names using their existing tooltip translations.
• Hide the CSS icons from the accessibility tree because the buttons now own the semantics.
• Make the rendering and tooltip tests select each action by role and name instead of toolbar order.

Behavior contract

• Assistive technology identifies all three plugin item actions by the same localized text sighted users receive in tooltips.
• Check for updates preserves release lookup, notification, and update-modal behavior.
• Plugin info preserves modal open and close behavior.
• Delete preserves confirmation, loading, uninstall, invalidation, callback, and error behavior.

Visual regression

No visual change is expected. This PR does not change elements, classes, styles, layout, node order, tooltip content, visibility conditions, or event handlers; it only adds ARIA attributes and strengthens the semantic rendering boundary.

The remaining positional queries in single-action functional scenarios are intentionally left for a dependent test-governance PR so this production fix stays compact.

Validation

• pnpm exec vp check app/components/plugins/plugin-item/action.tsx app/components/plugins/plugin-item/tests/action.spec.tsx (0 errors, 0 warnings)
• node scripts/lint-a11y.mjs app/components/plugins/plugin-item/action.tsx
• pnpm exec vp test run app/components/plugins/plugin-item/tests/action.spec.tsx (32/32)
• pnpm check (0 errors, 2059 existing warnings)

From Codex

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.42%. Comparing base (e036075) to head (a42d785).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #40261   +/-   ##
=======================================
  Coverage   86.41%   86.42%           
=======================================
  Files        5107     5107           
  Lines      290731   290752   +21     
  Branches    57917    57923    +6     
=======================================
+ Hits       251245   251270   +25     
+ Misses      34545    34541    -4     
  Partials     4941     4941           

Flag	Coverage Δ
dify-ui	93.49% <ø> (ø)
web	86.11% <100.00%> (+<0.01%)	⬆️

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