fix: support project-level orchestrator prompts with correct bootstrap refresh

[yaqub0r]

Summary

• support project-level orchestrator prompts for real chat/topic-backed orchestrator sessions
• keep winner-takes-all precedence so only one orchestrator prompt source is injected
• replace stale synthetic orchestrator.md content when bootstrap runs again for the same logical topic session

Problem

Worker prompts already support project-specific prompt files with clear precedence. Orchestrator prompts were lagging behind that model.

In the failing behavior:

• project-level orchestrator prompt resolution for real topic-bound orchestrator sessions was incomplete
• fallback behavior could be wrong for chat/topic-shaped session keys
• fresh bootstrap on the same logical topic session could keep older orchestrator prompt content instead of replacing it with the newly resolved winner

That made orchestrator prompt behavior inconsistent with other prompt types and made live validation misleading.

Testing

• human live validation passed on the self-hosted local-truth lane
• local promotion merged into devclaw-local-current via docs: Add DEMO.md with interactive walkthrough (#197) #198
• release hygiene follow-up removed local environment identifiers and local debug markers from upstream-facing test fixtures

Links

• local promotion tracker: UP: #195 rebootstrap topic-bound orchestrator prompts yaqub0r/devclaw#197
• upstream issue: Closes Support project-level orchestrator prompts with correct bootstrap refresh #540