Standardize shell-safe rendering of recreated CLI commands

Summary

Define and implement a consistent shell-safe rendering policy for recreated ROSA CLI commands.

Rationale

buildCommand renders a command for users to copy into a shell. It does not execute that command. Several user-controlled values are inserted into the rendered command without shell quoting. This includes comma-joined flag values and other string arguments. A targeted change for one flag would be inconsistent.

Affected areas

• cmd/create/cluster/cmd.go, especially buildCommand
• Equivalent recreated-command renderers in other CLI commands, if present
• Shared command-rendering or quoting helpers in pkg/helper
• Unit tests for command rendering

Required changes

1. Define which generated command values require shell-safe quoting.
2. Select or extend a shared helper for POSIX-shell-safe argument rendering.
3. Apply the policy consistently to recreated commands and their user-controlled arguments.
4. Preserve command semantics for normal values, lists, and intentionally empty values.
5. Add focused tests for spaces, quotes, shell metacharacters, and comma-joined values.

Acceptance criteria

• Generated recreation commands remain copy-paste safe for supported user input.
• Similar value types use the same quoting policy.
• Tests cover the shell-sensitive input cases.
• Documentation or code comments state the rendering policy and its scope.

Backlinks

• Pull request: https://github.com/openshift/rosa/pull/3500
• Review discussion: https://github.com/openshift/rosa/pull/3500#discussion_r3990744573
• Requested by: @michaelryanmcneill