feat(remote): add gh:org/repo[:branch] clone target

[gerchowl]

Description

Add gh:org/repo[:branch] target syntax to devc-remote.sh, enabling one-command clone-and-start of a project's devcontainer on a remote host. Existing host:path syntax continues to work unchanged.

Type of Change

• feat -- New feature
• fix -- Bug fix
• docs -- Documentation only
• chore -- Maintenance task (deps, config, etc.)
• refactor -- Code restructuring (no behavior change)
• test -- Adding or updating tests
• ci -- CI/CD pipeline changes
• build -- Build system or dependency changes
• revert -- Reverts a previous commit
• style -- Code style (formatting, whitespace)

Modifiers

• Breaking change (!) -- This change breaks backward compatibility

Changes Made

• scripts/devc-remote.sh — Extended parse_args to recognize gh:org/repo[:branch] as second positional arg; new remote_clone_project function (single SSH call: clone or fetch, optional branch checkout, config-based path resolution); wired into main() between check_ssh and remote_preflight; updated help text with new syntax and examples
• assets/workspace/scripts/devc-remote.sh — Synced copy via manifest
• tests/bats/devc-remote.bats — 7 new tests: 4 for arg parsing (gh:org/repo, gh:org/repo:branch, host:path+gh:, invalid gh:), 3 for clone function (fresh clone, fetch existing, branch checkout)
• CHANGELOG.md — Added entry under Unreleased

Changelog Entry

Added

• gh:org/repo[:branch] target for devc-remote (#236)
  • Clone a GitHub repo on the remote host and start its devcontainer in one command
  • Supports gh:org/repo (default branch) and gh:org/repo:branch (specific branch)
  • Already-cloned repos are fetched, not re-cloned
  • Clone location resolved from remote config projects_dir or overridden via host:path

Testing

• Tests pass locally (just test)
• Manual testing performed (describe below)

Manual Testing Details

N/A

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly (edit docs/templates/, then run just docs)
• I have updated CHANGELOG.md in the [Unreleased] section (and pasted the entry above)
• My changes generate no new warnings or errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

Additional Notes

Design: #236 (comment)

Refs: #236

[gerchowl]

Merged into feature/70-remote-devc-orchestration (PR #166)