add launchables support to create

[patelspratik]

Add a --launchable to create that least user's launch launcables

• Accept a launchable ID (env-XXX) or console URL (https://.../launchable/deploy?launchableID=env-XXX) via --launchable flag
• Fetch launchable details via GET /api/launchables/{id}/now and display name, description, instance type, storage, and build mode before creation
• Populate the full workspace request from the launchable: build config (VM/container/compose), port mappings, files, location, disk storage, and lifecycle scripts
• Set tracking labels (launchableId, launchableInstanceType, launchableCreatedByUserId, etc.) matching what the web UI sends

Flag interactions:

• --name is optional — defaults to sanitized launchable name with random 5-digit suffix (e.g., nemoclaw-fast-boot-04821)

• Build flags (--mode, --container-image, --compose-file, --startup-script, --jupyter) are ignored with a warning

• Instance flags (--type, --gpu-name, etc.) are allowed but warn that overriding is not recommended

• --dry-run shows launchable metadata and resolved instance type (works for both GPU and CPU instances)

• Merges labels with any existing labels instead of overwriting

• normalizeDiskStorage only appends Gi to bare numbers, passes through other suffixes

• Falls back to launchable's workspaceGroupID when CLI can't resolve from instance type mappings

• Reuses existing ssh.SanitizeNodeName for name sanitization