Add Session support to Kelos skill

[gjkim42]

What type of PR is this?

/kind docs

What this PR does / why we need it:

Updates the Kelos skill from the current personal skill while preserving the repository's progressive-disclosure structure.

The skill now covers Session resources, including worker and storage configuration, CLI operations, troubleshooting guidance, and reusable YAML examples.

Which issue(s) this PR is related to:

N/A

Special notes for your reviewer:

The shared Task, Workspace, AgentConfig, and TaskSpawner YAML references already matched the source skill, so this PR keeps them unchanged.

Validation:

• quick_validate.py skills/kelos
• git diff --check
• make verify (fails because pre-existing untracked get_helm.sh and .git/logs/refs/heads/support-skills.sh are included by the shell-format check)

Does this PR introduce a user-facing change?

The Kelos skill now supports authoring, operating, and troubleshooting Session resources.

---

Summary by cubic

Adds Session support to the Kelos skill so users can author, operate, and troubleshoot Session resources with clear examples and CLI guidance. Improves discoverability with concise docs and reusable YAML.

• New Features
  • Added Session docs to SKILL.md, including phases and reference to references/session.yaml.
  • Introduced references/session.yaml with ephemeral and persistent workspace examples, worker credentials, and PVC config.
  • Updated CLI and troubleshooting refs with kelos get sessions, kelos get session, kelos session connect, and delete commands, plus guidance for Sessions stuck in Pending/Failed.

^{Written for commit 2a348c5. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 4 files

_{Re-trigger cubic}