Add integration tests for MCPRemoteProxy resource references

[ChrisJBurns]

Summary

• Add integration tests for MCPRemoteProxy controller's integration with other resources (ExternalAuthConfigRef, ToolConfigRef, GroupRef)
• Add helper methods to reduce test duplication (WaitForPhase)
• Add builder methods for setting resource references (WithExternalAuthConfigRef, WithToolConfigRef, WithGroupRef)

Test Coverage Added

ExternalAuthConfigRef Integration (3 tests)

• Fails validation when referenced MCPExternalAuthConfig does not exist
• Successfully reconciles when referenced MCPExternalAuthConfig exists
• Triggers reconciliation when MCPExternalAuthConfig is updated (hash tracking)

ToolConfigRef Integration (3 tests)

• Fails validation when referenced MCPToolConfig does not exist
• Successfully reconciles when referenced MCPToolConfig exists
• Propagates tool config changes to the RunConfig ConfigMap (hash tracking)

GroupRef Integration (5 tests)

• Sets GroupRefValidated condition to False when MCPGroup does not exist
• Sets GroupRefValidated condition to True when MCPGroup exists and is Ready
• Sets GroupRefValidated condition to False when MCPGroup is not Ready
• Does not have GroupRefValidated condition when no GroupRef is specified
• Updates GroupRefValidated condition when MCPGroup becomes Ready

Test plan

• Tests compile successfully
• Code passes go vet and gofmt
• Tests pass in CI with envtest

Related Issues

Closes #3362 (Integration with Other Resources section)

See also #3607 for a follow-up to add structured status conditions for ToolConfigRef and ExternalAuthConfigRef validation.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.60%. Comparing base (f16d0cc) to head (fa890fc).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3608      +/-   ##
==========================================
- Coverage   65.61%   65.60%   -0.01%     
==========================================
  Files         407      407              
  Lines       40246    40246              
==========================================
- Hits        26407    26404       -3     
- Misses      11779    11781       +2     
- Partials     2060     2061       +1     

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