feat(skills): add vefaas-cli

[songhn233]

Change-Id: Ia56a8fc7b0c15b951e35434df52fd06d9a8c5160

[JiwaniZakir]

There's a typo in cookbooks/manage-functions.md line 4: "vefaas CLI installe" is missing the trailing d.

The deploy command pattern used throughout (--gatewayName $(vefaas run listgateways --first)) silently substitutes an empty string if no gateways are available, which would cause a confusing deployment failure. The docs should call out this failure mode and suggest verifying the output of vefaas run listgateways --first before piping it into deploy.

The .env.prod example in deploy-existing-code.md mixes quoted and unquoted values (PGPASSWORD=secret vs API_KEY="your-api-key"), which could mislead users about whether quoting is required — worth making the example consistent.

The SSO login step in SKILL.md notes it "opens browser, auto-completes when authorized" but the skill also claims to support CI/CD scenarios. There's no guidance on what happens in headless environments where a browser can't open — the AK/SK path should be mentioned as the fallback explicitly in that context rather than just listed in the table without cross-referencing.