Fix current-main CI blockers after M7 merge

[baron]

Summary

• replace yield-count polling in the workspace ingress fan-out test with actor-isolated count readiness while retaining the exact 8-before-release / 9-after-release contract
• keep response-delivery coverage on the contractual physical-delivery and drained end state without asserting transient unstructured-task registration order
• make the worktree smoke fixture complete the coordinator-owned MCP control-context/start-pending lifecycle for existing and created worktrees
• compile the connection-call-limiter debug snapshot alias only in DEBUG builds
• integrate current main at 191a1a6cab3aa28cb9ca8ea1ebc426dc26696bb4 with a normal merge commit

Validation

• exact three failing methods passed on the integrated head
• MCPDomainResponseDeliveryTrackerTests: 5/5 passed
• WorktreeAPISmokeHarnessTests: 6/6 passed
• WorkspaceFileContextStoreTests: 133/133 passed
• coordinated SwiftFormat + SwiftLint strict passed
• coordinated release preflight passed
• coordinated release artifact produced the arm64 release executable and cleared the original non-DEBUG compile failure; the ticket was externally canceled during the later x86_64 cold build after 5,284s, so it is not counted as a full artifact pass and hosted Release Candidate CI remains required
• commit-mode and push-mode contribution preflights passed

Scope

No workflow, packaging-flag, timeout, retry, or production-behavior changes. The release alias remains unavailable outside DEBUG.