fix(analysis): trim dialog commit input and guard worktree creation

Trim whitespace from interactive commit input in all parser dialogs
to prevent whitespace-only values from being passed as invalid commit
refs. Add guard in GitWorktreeManager.createWorktree() to prevent
multiple calls from orphaning previously created worktrees.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>