Fix bounded DMC lookup budget for Studio

[chubes4]

Summary

• raise the bounded DMC child lookup budget from 8 to 10 seconds for observed WordPress Studio startup time
• raise Homeboy provider supervision from 12 to 14 seconds, preserving the existing three-second cleanup and reporting margin
• make the realistic transport timing fixture prove that a 9-second startup floor succeeds
• retain deterministic timeout and descendant process-group reaping coverage

Closes #468.

Verification

• bash tests/homeboy-dmc-provider.sh
• php -l scripts/homeboy-dmc-provider.php
• bash -n lib/homeboy.sh
• bash -n tests/homeboy-dmc-provider.sh
• git diff --check
• Real WordPress Studio resolve_task replay returned typed worktree_not_found in 6.71 seconds against active Data Machine Code 0.71.1.

AI assistance

OpenAI GPT-5.6 Sol via OpenCode traced the layered Homeboy/DMC failures, measured the supported Studio transport floor, implemented the bounded timeout adjustment and regression, and ran the verification. Chris Huber directed the control-plane recovery and reviewed the scope.