test: add proxy scale and concurrency coverage

[RentnerKev]

Summary

Validate RentnerProxy behavior with substantially larger configurations
and concurrent management operations.

This is not a benchmark contest.

Goal is correctness and reasonable behavior under realistic scale.

Scenarios

Test representative workloads such as:

• 100 Proxy Hosts
• many domains
• Redirect Hosts
• certificates
• Access Policies
• concurrent host updates
• rapid desired-state changes
• coalesced reconciliation
• enable/disable bursts

Use actual reasonable numbers determined by runtime cost.

Verify

• no stale runtime configuration
• final desired revision wins
• no lost updates
• no concurrent apply corruption
• UI/API remains responsive enough
• Caddy config remains valid
• recovery works

Acceptance Criteria

• automated scale test
• concurrency test
• deterministic assertions
• no arbitrary performance threshold without evidence
• useful metrics/logs for failures

Priority

P1

Dependencies and sequencing

Build on completed revision/reconciliation semantics #12 and real smoke harnesses #13. Keep this correctness-at-scale work distinct from long-duration testing #69. Include final policy features where relevant. Results gate #75.

[github-actions]

🔍 Similar issues found

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Match	Issue	Status
Medium	#6 – [Bug]: test	CLOSED · COMPLETED

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