Add initial backend, CLI, and frontend scaffold

Bootstrap repository with multi-component scaffolding: a Spring Boot backend (Maven wrapper, pom.xml, BackendApplication, test, resources, .gitignore/.gitattributes), a Go CLI app using Cobra (root + subcommands: diff, log, login, pull, push, set, unset), prebuilt CLI binaries and a build script, and a Next.js frontend (configs, package.json, styles, pages, and static assets). This commit provides the skeleton for development across backend, CLI, and frontend components.

cli/go.mod

@@ -0,0 +1,37 @@
+module github.com/geneticglitch1/envsync-cli
+
+go 1.25.0
+
+require (
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
+	github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc // indirect
+	github.com/charmbracelet/lipgloss v1.1.0 // indirect
+	github.com/charmbracelet/x/ansi v0.8.0 // indirect
+	github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd // indirect
+	github.com/charmbracelet/x/term v0.2.1 // indirect
+	github.com/fsnotify/fsnotify v1.9.0 // indirect
+	github.com/go-resty/resty/v2 v2.17.2 // indirect
+	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/joho/godotenv v1.5.1 // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/muesli/termenv v0.16.0 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
+	github.com/sagikazarmark/locafero v0.11.0 // indirect
+	github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 // indirect
+	github.com/spf13/afero v1.15.0 // indirect
+	github.com/spf13/cast v1.10.0 // indirect
+	github.com/spf13/cobra v1.10.2 // indirect
+	github.com/spf13/pflag v1.0.10 // indirect
+	github.com/spf13/viper v1.21.0 // indirect
+	github.com/subosito/gotenv v1.6.0 // indirect
+	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
+	go.yaml.in/yaml/v3 v3.0.4 // indirect
+	golang.org/x/crypto v0.48.0 // indirect
+	golang.org/x/net v0.49.0 // indirect
+	golang.org/x/sys v0.41.0 // indirect
+	golang.org/x/text v0.34.0 // indirect
+)