feat: bake version into binary and display in UI sidebar

- Inject VERSION via ldflags (-X main=web.Version=) and git short SHA
- Add /api/version endpoint returning {version, commit}
- Display version in Layout sidebar footer (v0.1.6 · 8cfd405)
- Add AGENTS.md section documenting SemVer policy and bump-before-push rule
- Bump VERSION 0.1.5 -> 0.1.6 in Makefile

AGENTS.md

@@ -52,3 +52,24 @@ cd web && npm run dev   # Vite on :5173, proxies /api to :8080
 ```
 
 Requires `web/node_modules` (run `cd web && npm install` first).
+
+## Releasing / Versioning
+
+The project follows **SemVer**: `MAJOR.MINOR.PATCH`.
+
+- **PATCH** (`0.1.5 → 0.1.6`): bug fixes, no API changes.
+- **MINOR** (`0.1.x → 0.2.0`): new features, backward-compatible.
+- **MAJOR** (`0.x → 1.0`): breaking changes.
+
+**Bump before commit/push.** Update `VERSION?=` in the `Makefile` before staging any
+release-worthy changes. The value is baked into the binary at build time via
+`-ldflags -X github.com/darroyo/nasctl/internal/web.Version=$(VERSION)` and surfaced
+in the UI sidebar footer and `GET /api/version`.
+
+The short git SHA is also injected automatically via
+`-X github.com/darroyo/nasctl/internal/web.Commit=$(shell git rev-parse --short HEAD)`.
+
+Override at build time: `make build VERSION=0.2.0-rc1`.
+
+When reviewing staged changes, always confirm the version bump matches the
+nature of the change (patch vs minor vs major).

Makefile

@@ -1,7 +1,7 @@
 BINARY=nasctl
-VERSION?=0.1.5
+VERSION?=0.1.6
 GO?=go
-LDFLAGS=-s -w
+LDFLAGS=-s -w -X github.com/darroyo/nasctl/internal/web.Version=$(VERSION) -X github.com/darroyo/nasctl/internal/web.Commit=$(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
 BUILD_FLAGS=CGO_ENABLED=0
 
 .PHONY: build build-all frontend run package clean tidy test

cmd/nasctl/main.go

@@ -17,6 +17,11 @@ import (
 	"github.com/darroyo/nasctl/internal/web"
 )
 
+var (
+	version = "dev"
+	commit  = ""
+)
+
 func main() {
 	addr := flag.String("addr", envOrDefault("NASCTL_ADDR", ":8080"), "HTTP listen address")
 	dbPath := flag.String("db", envOrDefault("NASCTL_DB", "/var/lib/nasctl/nasctl.db"), "SQLite database path")
@@ -79,6 +84,7 @@ func main() {
 	})
 
 	eng := engine.New(sambaModule, nfsModule, usersModule)
+	web.SetVersionInfo(version, commit)
 	srv := web.NewServer(database, eng, web.Options{
 		AllowedRoots: parseRoots(*allowedRoots),
 		Auth:         auth,
@@ -86,7 +92,7 @@ func main() {
 		ExportsPath:  *exportsPath,
 	})
 
-	log.Printf("nasctl listening on %s (db=%s exec-system=%v)", *addr, *dbPath, *execSystem)
+	log.Printf("nasctl %s (commit %s) listening on %s (db=%s exec-system=%v)", version, commit, *addr, *dbPath, *execSystem)
 	if err := http.ListenAndServe(*addr, srv.Handler()); err != nil {
 		log.Fatalf("server error: %v", err)
 	}

internal/web/handlers_system.go

@@ -37,6 +37,13 @@ func (s *Server) handleSystemStatus(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, status)
 }
 
+func (s *Server) handleVersion(w http.ResponseWriter, r *http.Request) {
+	writeJSON(w, http.StatusOK, map[string]string{
+		"version": Version,
+		"commit":  Commit,
+	})
+}
+
 func (s *Server) collectDiskUsage() []diskUsage {
 	entries := make(map[string]*diskUsage)
 

internal/web/router.go

@@ -29,6 +29,7 @@ func NewRouter(s *Server) chi.Router {
 			protected.Post("/apply", s.handleApply)
 			protected.Get("/apply/log", s.handleApplyLog)
 			protected.Get("/system/status", s.handleSystemStatus)
+			protected.Get("/version", s.handleVersion)
 			protected.Put("/auth/password", s.handleChangePassword)
 
 			protected.Get("/import/status", s.handleImportStatus)

internal/web/version.go

@@ -0,0 +1,11 @@
+package web
+
+var (
+	Version = "dev"
+	Commit  = ""
+)
+
+func SetVersionInfo(v, c string) {
+	Version = v
+	Commit = c
+}

web/src/api.ts

@@ -65,6 +65,11 @@ export interface SystemStatus {
   services: ServiceStatus[];
 }
 
+export interface VersionInfo {
+  version: string;
+  commit: string;
+}
+
 export class ApiError extends Error {
   status: number;
   constructor(status: number, message: string) {
@@ -104,6 +109,7 @@ export const api = {
   apply: () => request<{ results: { module: string; applied: boolean; error?: string }[] }>("POST", "/apply"),
   applyLog: () => request<{ entries: ApplyLogEntry[] }>("GET", "/apply/log"),
   systemStatus: () => request<SystemStatus>("GET", "/system/status"),
+  version: () => request<VersionInfo>("GET", "/version"),
 
   // samba
   listShares: () => request<{ shares: SambaShare[] | null }>("GET", "/samba/shares/"),

web/src/components/Layout.tsx

@@ -1,5 +1,6 @@
+import { useEffect, useState } from "react";
 import { NavLink, Outlet, useNavigate } from "react-router-dom";
-import { api } from "../api";
+import { api, VersionInfo } from "../api";
 import DirtyBanner from "./DirtyBanner";
 
 const navItems = [
@@ -13,6 +14,11 @@ const navItems = [
 
 export default function Layout({ username, onLogout }: { username: string; onLogout: () => void }) {
   const navigate = useNavigate();
+  const [version, setVersion] = useState<VersionInfo | null>(null);
+
+  useEffect(() => {
+    api.version().then(setVersion).catch(() => {});
+  }, []);
 
   async function handleLogout() {
     await api.logout();
@@ -47,6 +53,9 @@ export default function Layout({ username, onLogout }: { username: string; onLog
           <button className="btn-ghost w-full" onClick={handleLogout}>
             Cerrar sesión
           </button>
+          <div className="mt-2 border-t border-slate-800 pt-2 text-center font-mono text-xs text-slate-600">
+            v{version?.version ?? "dev"}{version?.commit && ` · ${version.commit}`}
+          </div>
         </div>
       </aside>
       <main className="flex-1">