Fix epic plan revision loop

[eshulman2]

Summary

• clear plan revision markers after successful epic decomposition/regeneration
• clear task revision markers after successful task generation/regeneration
• resume regenerate_all_epics and update_single_epic at their own nodes instead of raw decomposition
• resume PRD/spec/task/RCA regeneration nodes at their own cleanup paths
• preserve Epic source when task-review feedback is left on an Epic
• post Jira acknowledgements when question/revision resume comments are accepted
• add regression tests for the stale revision loop and resume routing

Tests

• UV_CACHE_DIR=/tmp/uv-cache JIRA_BASE_URL=https://example.atlassian.net JIRA_API_TOKEN=dummy JIRA_USER_EMAIL=test@example.com GITHUB_TOKEN=dummy uv run pytest tests/unit/workflow/nodes/test_epic_decomposition.py tests/unit/workflow/nodes/test_task_generation.py tests/unit/orchestrator/gates/test_plan_approval.py tests/unit/orchestrator/gates/test_task_approval.py tests/unit/workflow/feature/test_workflow.py tests/unit/workflow/bug/test_graph.py tests/unit/orchestrator/test_worker.py tests/unit/orchestrator/test_worker_option_detection.py
• uv run ruff check src/forge/workflow/nodes/epic_decomposition.py src/forge/workflow/nodes/task_generation.py src/forge/workflow/feature/graph.py src/forge/workflow/bug/graph.py src/forge/orchestrator/worker.py tests/unit/workflow/nodes/test_epic_decomposition.py tests/unit/workflow/nodes/test_task_generation.py tests/unit/workflow/feature/test_workflow.py tests/unit/workflow/bug/test_graph.py tests/unit/orchestrator/gates/test_task_approval.py tests/unit/orchestrator/test_worker.py tests/unit/orchestrator/test_worker_option_detection.py