Harden gof init for paths, Postgres ports, and failed-run cleanup

[iamtemi]

Summary

• Split init path vs project name so absolute paths don't become invalid Docker container names
• Fail fast when the Postgres host port is in use, with --postgres-port to remap
• Roll back the project directory (and compose resources) if init fails mid-run
• Clean up download/unzip artifacts on failed template fetch

Test plan

• gof init goapp in an empty dir succeeds
• gof init codebase/goapp uses basename goapp for container names
• With something on :5432, init fails and suggests --postgres-port
• Forced mid-init failure leaves no leftover project folder