fix(init): don't require SFTP account for cf init and non-SFTP commands (2.4.1)

[jeffdi]

Summary

A user reported that after cf login the cf init command aborted with

No SFTP account linked to your platform account. Please run 'cf login' first.

The message is misleading: login had already succeeded, but the user's account had no SFTP account provisioned yet (SFTP accounts are auto-provisioned server-side only after a project deposit is paid/waived/sponsored and an SSH key is on the user's profile — see _auto_provision_sftp_if_eligible in chipignite-backend-services/src/user_service/routes.py). A user evaluating the tooling before committing to a shuttle had no way past init.

The sftp_username is only needed for commands that actually talk to SFTP. Everywhere else it was used only as a label in .cf/project.json that the backend stores as an opaque blob and the CLI never reads back. This PR loosens the gating so new users can onboard end-to-end without an SFTP account and only hit the gate when they actually need SFTP.

Behavior matrix after the fix

Command	Works without SFTP account?
cf login, cf logout, cf whoami, cf keygen, cf config	yes (already did)
cf init, cf link, cf unlink	yes (changed)
cf gpio-config, cf precheck (local), cf precheck --remote, cf push --remote	yes (already did)
cf status (platform half)	yes — SFTP half now skipped gracefully (changed)
cf push (SFTP), cf pull, cf tapeouts, cf confirm	no — gate preserved with a clearer, eligibility-aware message

Changes

• cf init: no longer aborts when sftp_username is missing. Refreshes from /auth/cli/whoami only when an API key is present; falls back to user_email (or "unknown") for the proj['user'] metadata field. The rest of the init flow is already API-key driven.
• cf status: the SFTP listing becomes a best-effort extra. When no SFTP account is linked, the command prints the platform status, emits a soft hint, and exits cleanly instead of aborting after already showing useful output.
• cf push (SFTP path), cf pull, cf tapeouts, cf confirm: the four legitimate SFTP gates keep blocking, but the message now explains the auto-provisioning rules ("provisioned once a project deposit is paid/waived/sponsored and an SSH public key is on your profile") instead of telling users to contact support.
• Patch bump to 2.4.1 in pyproject.toml. Also aligns chipfoundry_cli/__init__.py which had drifted at 2.3.2.

Test plan

• pytest full suite: 125 passed, 1 skipped
• Manual: run cf login with a brand-new account (no SFTP linked), then cf init in an empty project directory — expect success (previously aborted).
• Manual: on the same account run cf status — expect platform status to print, followed by the SFTP-skipped hint, exit 0.
• Manual: on the same account run cf push (SFTP) and cf pull — expect the new eligibility-aware error message and non-zero exit.
• Manual: on an eligible account, verify cf init, cf push, and cf pull behave as before.
• Manual: verify cf precheck --remote and cf push --remote continue to work for eligible users (no regressions from reorder of api_key/username in cf init).