Sanitize Linear text in CLI and SSH terminal output #20478

Summary

Add a shared sanitizer for all Linear text that is rendered in terminal output.

Rationale

The Linear CLI formatter and the SSH fallback formatter currently write Linear-provided text directly to terminal output. A sanitizer must apply consistently to every rendered Linear text field. Sanitizing only the cycle name would make that field inconsistent with the surrounding fields.

Affected areas

• src/cli/linear-format.ts
• src/main/ssh/ssh-remote-linear-output.ts
• Shared Linear formatting utilities, including src/shared/linear/cycle-label.ts where applicable

Required changes

• Define a shared sanitizer for Linear text intended for terminal output.
• Apply the sanitizer to issue title, state name, assignee name, project name, label names, and cycle name in both formatter paths.
• Prevent terminal control characters, including line breaks and ANSI/OSC escape sequences, from changing terminal output structure or behavior.
• Preserve existing display behavior for ordinary printable Linear text.
• Add regression tests for malicious or malformed Linear text in both standard CLI and SSH fallback output.

Acceptance criteria

• Both formatter paths use the same sanitizer.
• All rendered Linear text fields use the sanitizer.
• Tests cover control-character inputs and confirm that terminal control sequences do not pass through.
• Existing tests for normal issue output continue to pass.

Backlinks

• Pull request: feat(linear): expose the cycle number on issue results #20409
• Review discussion: feat(linear): expose the cycle number on issue results #20409 (comment)

Requested by @luanAfons0.