fix: handle GitHub monorepo URLs in apply flow

[bryantgillespie]

Closes #122.

Summary

• Users entering a monorepo root URL (e.g. https://github.com/directus-labs/starters/) previously hit TypeError: Cannot read properties of null (reading 'templateName'). Now the CLI walks nested dirs and either auto-selects the single template found, prompts the user to pick when multiple exist, or errors clearly when none.
• transformGitHubUrl hardened: tolerates trailing slashes, .git suffix, preserves /tree/<ref>/... branch refs (previously silently discarded), throws on unparseable input instead of returning the literal string "Invalid URL".
• Programmatic mode (-p --templateType=github) gets an actionable error listing copy-pasteable --templateLocation="..." URLs for each discovered template. Single-nested case auto-descends with a warning suggesting the user pin the full URL to avoid surprises if more templates are added to the repo later.

What changed

• src/lib/utils/transform-github-url.ts — extracted parseGitHubUrl helper; hardened regex.
• src/lib/utils/get-template.ts — new getInteractiveGithubTemplate returning Template[]; getGithubTemplate now uses shared download helper and emits actionable errors.
• src/commands/apply.ts — new selectGithubTemplate method mirroring selectLocalTemplate pattern.

Test plan

• pnpm tsc --noEmit passes
• Interactive apply against https://github.com/directus-labs/starters/ — shows picker with CMS / CMS - i18n
• Interactive apply against .../tree/main/cms/directus/template — auto-selects single template
• Interactive apply against URL with trailing slash / .git — handled
• Programmatic apply -p --templateType=github --templateLocation="https://github.com/directus-labs/starters/" — errors with copy-pasteable list
• Garbage URL — clean Invalid GitHub URL error

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Improves the CLI “apply” flow for GitHub-hosted templates by correctly handling monorepo root URLs and preserving branch refs, preventing null-template crashes and providing actionable selection/error paths.

Changes:

• Added robust GitHub URL parsing and ref/subpath preservation (trailing slash / .git tolerant).
• Enhanced GitHub template discovery by walking nested directories and producing clearer outcomes for 0/1/many templates.
• Added interactive GitHub template selection in apply, mirroring the local template selection UX.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
src/lib/utils/transform-github-url.ts	Adds parseGitHubUrl and updates URL transformation to preserve /tree/<ref>/... and reject invalid inputs.
src/lib/utils/get-template.ts	Adds shared GitHub download helper, nested template discovery behavior, and a new interactive GitHub template getter.
src/commands/apply.ts	Introduces interactive template selection for GitHub URLs via selectGithubTemplate.

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