CONTRIBUTING.md worktree path format contradicts docs/github-workflow.md

[codeforester]

Problem

CONTRIBUTING.md (step 4) shows a relative worktree path:

git worktree add ../base-worktrees/<slug> -b <branch> origin/master

docs/github-workflow.md shows an absolute worktree path:

git fetch origin master
git worktree add -b documentation/241-20260529-document-github-workflow \
  ~/work/base-worktrees/documentation-241-github-workflow origin/master

The two documents describe the same workflow but use different path formats:

• CONTRIBUTING.md uses ../base-worktrees/<slug> (relative, from within ~/work/base/)
• github-workflow.md uses ~/work/base-worktrees/<slug> (absolute)

The argument order also differs: CONTRIBUTING.md puts the path before -b <branch>, while github-workflow.md puts -b <branch> before the path. Both are valid git worktree add syntax, but the inconsistency is confusing.

Fix

Align both documents to use the absolute path form from github-workflow.md. Update CONTRIBUTING.md step 4 to:

git fetch origin master
git worktree add -b <branch> ~/work/base-worktrees/<slug> origin/master

Also add the cleanup step to CONTRIBUTING.md step 8 (currently says "remove the worktree" without the command):

git -C ~/work/base pull --ff-only origin master
git -C ~/work/base worktree remove ~/work/base-worktrees/<slug>
git -C ~/work/base branch -d <branch>
git -C ~/work/base push origin --delete <branch>

This matches the full cleanup sequence in github-workflow.md.