feat(P01): CLI skeleton with Cobra, subcommand stubs, pre-push hook

Implements Phase 1 of v0.1 Foundation:
- go.mod with Go 1.25
- cmd/orca/main.go entry point
- internal/cli/root.go with global --json flag
- internal/cli/version.go (orca version)
- internal/cli/init.go (orca init - creates ~/.orca/)
- internal/cli/status.go (orca status - shows daemon info)
- internal/cli/node.go (orca node {join,leave,list} - stubs)
- internal/cli/job.go (orca job {run,list,stop,logs} - stubs)
- Makefile (build, test, lint, fmt, release)
- LICENSE (MIT)
- README.md with quickstart
- .gitignore
- .githooks/pre-push + scripts/trigger_coreci.sh (CoreCI trigger)
- Smoke tests in internal/cli/root_test.go

Verified: go build, go test, go vet, gofmt all pass.

---ci---
project: orca
phase: 1
milestone: v0.1
status: execute
req_covered:
  - REQ-001
  - REQ-002
  - REQ-013
  - REQ-015
  - REQ-016
  - REQ-019
  - REQ-024
---/ci---

internal/cli/root.go

@@ -0,0 +1,52 @@
+package cli
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+var (
+	version   = "0.1.0-dev"
+	gitCommit = "unknown"
+	buildTime = "unknown"
+)
+
+var rootCmd = &cobra.Command{
+	Use:   "orca",
+	Short: "Orca — offline/CLI-first orchestration engine",
+	Long: `Orca is a minimalist, offline-first, CLI-first orchestration engine
+inspired by HashiCorp Nomad, prioritizing stability, security, and simplicity
+over feature richness.`,
+	SilenceUsage:  true,
+	SilenceErrors: true,
+}
+
+var jsonOutput bool
+
+func init() {
+	rootCmd.PersistentFlags().BoolVar(&jsonOutput, "json", false, "output in JSON format")
+}
+
+func Execute() error {
+	return rootCmd.Execute()
+}
+
+func printJSON(v any) error {
+	enc := json.NewEncoder(rootCmd.OutOrStdout())
+	enc.SetIndent("", "  ")
+	return enc.Encode(v)
+}
+
+func printText(format string, args ...any) {
+	fmt.Fprintf(rootCmd.OutOrStdout(), format, args...)
+}
+
+func printResult(text string, jsonObj any) {
+	if jsonOutput {
+		_ = printJSON(jsonObj)
+		return
+	}
+	printText("%s\n", text)
+}