ci: add local checks (make check, pre-commit hook) and Gitea Actions workflow skeleton

Makefile

@@ -3,7 +3,7 @@ BINARY   := gitlink-cli
 VERSION  ?= $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
 LDFLAGS  := -s -w -X '$(MODULE)/cmd.Version=$(VERSION)'
 
-.PHONY: build install clean test
+.PHONY: build install clean test check vet fmt cover
 
 build:
 	go build -ldflags "$(LDFLAGS)" -o $(BINARY) .
@@ -15,4 +15,27 @@ clean:
 	rm -f $(BINARY)
 
 test:
-	go test ./...
+	go test -race ./...
+
+vet:
+	go vet ./...
+
+fmt:
+	@unformatted=$$(gofmt -s -l .); \
+	if [ -n "$$unformatted" ]; then \
+		echo "Files not formatted:"; \
+		echo "$$unformatted"; \
+		exit 1; \
+	fi
+
+cover:
+	go test -coverprofile=coverage.out ./...
+	go tool cover -func=coverage.out
+
+check: fmt vet test
+	@echo "All checks passed."
+
+hooks:
+	cp scripts/pre-commit .git/hooks/pre-commit
+	chmod +x .git/hooks/pre-commit
+	@echo "Pre-commit hook installed."

scripts/pre-commit

@@ -0,0 +1,25 @@
+#!/bin/sh
+# Pre-commit hook: run fmt + vet + test before every commit.
+# Install: make hooks
+
+set -e
+
+echo "=== gofmt ==="
+unformatted=$(gofmt -s -l .)
+if [ -n "$unformatted" ]; then
+  echo "ERROR: these files are not formatted:"
+  echo "$unformatted"
+  echo "Run: gofmt -s -w ."
+  exit 1
+fi
+echo "  OK"
+
+echo "=== go vet ==="
+go vet ./...
+echo "  OK"
+
+echo "=== go test ==="
+go test -race ./...
+echo "  OK"
+
+echo "=== pre-commit passed ==="