Rebrand from act_runner to gitcaddy-runner v1.0.0

- Update module path: gitea.com/gitea/act_runner → git.marketally.com/gitcaddy/gitcaddy-runner
- Update all import paths across Go source files
- Update Makefile LDFLAGS and package references
- Update .goreleaser.yaml ldflags and S3 directory path
- Add comprehensive README with capacity configuration documentation
- Document troubleshooting for capacity feature and Docker detection
- Bump version to v1.0.0 for major rebrand
- All linting checks passed (fmt-check, go mod tidy, go vet)

main.go

@@ -8,7 +8,7 @@ import (
 	"os/signal"
 	"syscall"
 
-	"gitea.com/gitea/act_runner/internal/app/cmd"
+	"git.marketally.com/gitcaddy/gitcaddy-runner/internal/app/cmd"
 )
 
 func main() {