Add Go module scaffold with dependencies and entrypoint

Initialize the publix-deals Go module (go 1.24.4) with core
dependencies: cobra for CLI structure, lipgloss for styled terminal
output, testify for assertions, and x/term for TTY detection.

The main entrypoint at cmd/pubcli/main.go delegates to cmd.Execute().
The .gitignore covers Go build artifacts, editor files, coverage
output, and jj VCS state.

.gitignore

@@ -0,0 +1,48 @@
+# Go binaries and build outputs
+/pubcli
+/publix-deals
+/bin/
+/build/
+/dist/
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+*.test
+
+# Go test, coverage, and profiling artifacts
+*.out
+coverage.out
+coverage.txt
+*.coverprofile
+*.prof
+*.pprof
+
+# Local Go tool caches
+.gocache/
+.gomodcache/
+
+# Environment and local overrides
+.env
+.env.*
+!.env.example
+
+# Editor and IDE files
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Local temp/log files
+*.log
+tmp/
+temp/
+
+# Local VCS helper state
+.jj/