Add a user-facing setting to hide the commit message input box in the Source Control panel.

Use Case

When using VS Code with multiple repositories in a workspace, the Source Control panel displays a commit input box for each repository. For users who:

• Prefer committing via terminal/CLI (e.g., using Claude Code, git CLI, or other tools)
• Want a cleaner, more compact Source Control view
• Only use the panel to view changed files, not to commit

The input boxes take up significant vertical space (34px per repository) and cannot currently be hidden.

Current Workarounds

• scm.inputMinLineCount: 1 and scm.inputMaxLineCount: 1 reduce height but don't hide the box
• CSS injection via extensions can hide the content but cannot collapse the gap due to VS Code's virtualized list using JavaScript-calculated inline styles for row positioning
• The SourceControlInputBox.visible property exists in the API but is only accessible to SCM provider extensions, not end users

Proposed Solution

Add a setting like:

"scm.showInputBox": false

Or per-provider:

"git.showInputBox": false

This would:

1. Hide the input box rows in the Source Control panel
2. Collapse the space they occupy (update the virtualized list to skip these rows)
3. Still allow commits via command palette, terminal, or other means

Additional Context

• Related: The git.showActionButton setting successfully hides commit/sync/publish buttons
• Related: SourceControlInputBox.visible API exists for extension authors (issue Test: Hide SCM commit input box #62068, PR Allow scc providers hide commit input box. #60051)
• This would bring user-facing parity with what extension authors can already do programmatically

System Info

• VS Code Version: 1.106.3 (latest stable)
• OS: Linux (Arch)