dns: fix CNAME answer, mixed-case queries and more

[BeryJu]

• Improved DNS Testing helpers (already helped find some bugs)
• Fix CNAME records not being added to answer when not explicitly querying CNAME
• Fixed mixed-case queries not returning in the case saved in etcd
• Fixed CNAME recursion limit not applying correctly
• Fix other misc things

[netlify]

✅ Deploy Preview for beryju-gravity canceled.

Name	Link
🔨 Latest commit	b0407b9
🔍 Latest deploy log	https://app.netlify.com/sites/beryju-gravity/deploys/677a109851012a000866e892

[codecov]

Bundle Report

Bundle size has no change ✅

[codecov]

Codecov Report

Attention: Patch coverage is 91.11111% with 4 lines in your changes missing coverage. Please review.

Project coverage is 59.86%. Comparing base (12c962a) to head (b0407b9).
Report is 2 commits behind head on main.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
pkg/roles/dns/zone_watch.go	0.00%	1 Missing and 1 partial ⚠️
pkg/roles/dns/dns_handler.go	0.00%	1 Missing ⚠️
pkg/roles/dns/role.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1397      +/-   ##
==========================================
- Coverage   60.05%   59.86%   -0.20%     
==========================================
  Files         137      137              
  Lines        7641     7654      +13     
==========================================
- Hits         4589     4582       -7     
- Misses       2605     2626      +21     
+ Partials      447      446       -1     

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