feat(cli): add --dockerfile-location to application create and update

[paoValle]

Summary

Adds --dockerfile-location to the repository-based application commands (app create public, app create github, app create deploy-key) and to app update, mapped to the API's dockerfile_location. The sibling build option (--dockerfile-target-build) was already exposed, so an application whose Dockerfile lives in a subdirectory of a monorepo could be created from the CLI but not pointed at that Dockerfile.

Changes

• internal/models/application.go: DockerfileLocation on ApplicationCreatePublicRequest, ApplicationCreateGitHubAppRequest, ApplicationCreateDeployKeyRequest and ApplicationUpdateRequest (json:"dockerfile_location,omitempty").
• The flag is registered and applied on the four matching commands. The inline dockerfile create and the dockerimage create do not get it: neither request body accepts the field.
• README.md: the flag is listed for app update and for the create commands.
• llms.txt / llms-full.txt regenerated with go run ./coolify docs llms.

Verification

• go build ./... — clean
• go test ./cmd/... ./internal/... — all packages pass, including the new TestDockerfileLocation_MarshalRequestShape, TestDockerfileLocation_OmittedWhenUnset, TestGitCreateCommands_ExposeDockerfileLocationFlag
• go run ./coolify docs llms produces a byte-identical llms.txt / llms-full.txt
• gofmt -l . empty; golangci-lint run ./cmd/... ./internal/... reports the same 6 findings as upstream/main (3 gosec in test files, 3 govet in internal/output/table.go), so none is new

Closes #97