feat: initialize Go module and project directory skeleton

Tasks 0.1 and 0.2 — set up the cmd/internal project layout with a
minimal main.go that prints version and exits. Directory structure
maps each architecture component to an internal sub-package.

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Author: sergeyklay

cmd/sortie/main.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+// Version is set at build time via -ldflags.
+var Version = "dev"
+
+func main() {
+	fmt.Printf("sortie %s\n", Version)
+	os.Exit(0)
+}

go.mod

@@ -0,0 +1,19 @@
+// Project layout: cmd/internal pattern (Go standard project layout).
+//
+// cmd/sortie/          — main entry point, CLI flag parsing
+// internal/domain/     — domain types: Issue, TrackerAdapter, AgentAdapter interfaces
+// internal/config/     — workflow loader, typed config, prompt template rendering
+// internal/orchestrator/ — poll loop, dispatch, reconciliation, retry, state machine
+// internal/tracker/    — tracker adapter implementations (jira, file, etc.)
+// internal/agent/      — agent adapter implementations (claude-code, mock, etc.)
+// internal/workspace/  — workspace creation, path safety, hook execution
+// internal/server/     — HTTP API and dashboard
+//
+// Rationale: the cmd/internal split is the dominant Go convention. The internal/
+// directory enforces package-level encapsulation at the compiler level — external
+// consumers cannot import internal packages. Each architecture component maps to
+// one internal sub-package, keeping dependencies explicit and testable in isolation.
+
+module github.com/sortie-ai/sortie
+
+go 1.26.1