fix: restrict credential access to editors

[Jozsef Damokos (jozsefdamokos)]

• Hide stored credentials from the generic API and load them through an editor-only endpoint in the wizard.
• Require editor permission to check replacement credentials while preserving viewer checks of saved connections.

[codecov]

Codecov Report

❌ Patch coverage is 9.09091% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 65.32%. Comparing base (d191cfc) to head (0ad2df0).
⚠️ Report is 1 commits behind head on trunk.

Files with missing lines	Patch %	Lines
src/Controller/StatusController.php	0.00%	10 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk     #233      +/-   ##
============================================
- Coverage     65.36%   65.32%   -0.04%     
- Complexity     4786     4790       +4     
============================================
  Files           654      654              
  Lines         21756    21766      +10     
============================================
- Hits          14221    14219       -2     
- Misses         7535     7547      +12     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.