feat: dual execution model (SSH CLI + HTTP pull)

- ExecutionMode enum: SshCli (orchestrator dispatches) | HttpPull (agent pulls)
- SSH CLI executor: spawn remote agents via ssh + CLI template
- Local subprocess as SSH special case (localhost)
- HostConfig with capability matching and load-based selection
- Dispatch loop: scan created tasks → select host → execute → update
- CliAdapterConfig: CLI templates for Codex and Claude Code
- Structured prompt construction (Issue → goal/constraints/validation)
- Output parsers: Codex JSON, Claude Code JSON, raw fallback
- TaskStatus::ReviewPending + review_count loop limit
- Forgejo webhook: pull_request (opened→review_pending, merged→completed)
- Forgejo webhook: push events (task/* branch → last_activity_at)
- HTTP API: dequeue only returns http_pull tasks
- HTTP API: status update only for http_pull mode
- Token auth config for http_pull agents
- Adapter module rewritten: AgentAdapter trait removed → config-driven CLI templates
- New fields: execution_mode, assigned_host, branch_name, pr_title, last_activity_at, review_count
- 30/30 tests pass

openspec/changes/adapter-cross-machine-revision/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-05-12