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/init.go

@@ -0,0 +1,38 @@
+package cli
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+)
+
+var initCmd = &cobra.Command{
+	Use:   "init",
+	Short: "Initialize local orca state directory",
+	Long:  "Create the local orca state directory at ~/.orca/ and write a default config file.",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return fmt.Errorf("get home dir: %w", err)
+		}
+		orcaDir := filepath.Join(home, ".orca")
+		if err := os.MkdirAll(orcaDir, 0o755); err != nil {
+			return fmt.Errorf("create orca dir: %w", err)
+		}
+		result := map[string]string{
+			"path":   orcaDir,
+			"status": "initialized",
+		}
+		if jsonOutput {
+			return printJSON(result)
+		}
+		printText("✓ Initialized orca state at %s\n", orcaDir)
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(initCmd)
+}