feat: implement proper orchestrator workflow with reconciliation loop

Rewrite OrchestratorWorkflow as true reconciliation loop:
- PlanningActivity decides what tasks to dispatch
- Fan-out TaskUnit workflows for parallel execution
- Each TaskUnit runs Implementer → Test → Judge → Commit
- Judge reviews code quality, retries on failure with lessons
- Fan-in waits for all TaskUnits
- Board update and squash merge on success
- continue-as-new for long-running workflows
- Proper error handling and signal support

Key changes:
- statemachine/orchestrator.go: Reconciliation loop (Plan → Dispatch → Review → Repeat)
- statemachine/taskunit.go: Task execution with retry loop & judge review
- statemachine/types.go: Updated TaskUnitInput/Output for new workflow
- cmd/worker/main.go: Register RunIntegrationTestActivity
- action/integration.go: Renamed from integration_test.go (fix Go build issue)

Models:
- Planner: reasoning (OpenAI-compatible from local LLM API)
- Judge: reasoning (reviews diff + tests, gates success)
- Implementer: ornith:35b (executes tasks)

Verification: go build ./cmd/worker ./cmd/starter ✓

action/integration.go

@@ -0,0 +1,43 @@
+package action
+
+import (
+	"context"
+	"os/exec"
+)
+
+// RunIntegrationTestInput is input to RunIntegrationTestActivity.
+type RunIntegrationTestInput struct {
+	WorktreePath string
+	TestCmd      string
+}
+
+// RunIntegrationTestOutput is the output of RunIntegrationTestActivity.
+type RunIntegrationTestOutput struct {
+	Passed bool
+	Logs   string
+}
+
+// RunIntegrationTestActivity runs integration tests in the worktree.
+func RunIntegrationTestActivity(ctx context.Context, in RunIntegrationTestInput) (RunIntegrationTestOutput, error) {
+	if in.TestCmd == "" {
+		// No test command, assume pass
+		return RunIntegrationTestOutput{Passed: true, Logs: "No test command provided"}, nil
+	}
+
+	// Run test command
+	cmd := exec.CommandContext(ctx, "sh", "-c", in.TestCmd)
+	cmd.Dir = in.WorktreePath
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return RunIntegrationTestOutput{
+			Passed: false,
+			Logs:   string(output) + "\nError: " + err.Error(),
+		}, nil
+	}
+
+	return RunIntegrationTestOutput{
+		Passed: true,
+		Logs:   string(output),
+	}, nil
+}