feat: add product improvements — version, aliases, auto-slug, wt-cd, wt-open, wt-reopen, --json, init, env vars (#14)

Major new features and CLI ergonomics improvements:

- `wtf version` command (table-stakes for any CLI tool)
- Command aliases: new, pub, pr, up, clean, ls, st, cd, open, reopen
- Auto-detect SLUG from current worktree (no more typing slug every time)
- `wtf wt-cd SLUG` — print worktree path for shell composition
- `wtf wt-open SLUG` — open worktree in editor ($EDITOR/code/vim/nano)
- `wtf wt-reopen SLUG` — recreate worktree from existing remote branch
- `wtf init` — interactive config wizard for .worktreeflow.toml
- `--json` global flag for machine-readable output (doctor, wt-list, wt-status)
- `--open` flag on wt-new to open editor after creation
- Environment variable overrides: WTF_BASE_BRANCH, WTF_DEBUG, WTF_DRY_RUN, etc.
- Enhanced wt-list: last activity dates, stale worktree detection (30+ days), PR status
- Centralized `_require_gh()` for consistent gh CLI prerequisite checks
- Updated tutorial and quickstart with all new features
- 30 new tests (158 total), all passing with clean lint

https://claude.ai/code/session_01A1Z3oDtv65NzXVqYaSsn8G

Co-authored-by: Claude <noreply@anthropic.com>

Author: smorin

src/worktreeflow/cli.py

@@ -157,3 +157,45 @@ def load_config(repo_root: Path | None = None) -> RepoSettings:
             setattr(RepoConfig, repo_config_attr, merged[toml_key])
 
     return settings
+
+
+def generate_config(
+    upstream_repo: str | None = None,
+    base_branch: str = "main",
+    feature_branch_prefix: str = "feat/",
+    use_ssh: bool = True,
+    auto_stash: bool = False,
+    create_backup_branches: bool = True,
+    default_draft_pr: bool = False,
+) -> str:
+    """
+    Generate a .worktreeflow.toml config file content.
+
+    Args:
+        upstream_repo: Upstream repo in owner/repo format.
+        base_branch: Base branch name.
+        feature_branch_prefix: Prefix for feature branches.
+        use_ssh: Whether to use SSH URLs.
+        auto_stash: Whether to auto-stash during updates.
+        create_backup_branches: Whether to create backups.
+        default_draft_pr: Whether to create PRs as drafts.
+
+    Returns:
+        TOML file content as a string.
+    """
+    lines = ["# worktreeflow configuration", "# See: https://github.com/smorinlabs/worktreeflow", ""]
+    lines.append("[repo]")
+    if upstream_repo:
+        lines.append(f'upstream_repo = "{upstream_repo}"')
+    lines.append(f'base_branch = "{base_branch}"')
+    lines.append(f"use_ssh = {'true' if use_ssh else 'false'}")
+    lines.append("")
+    lines.append("[workflow]")
+    lines.append(f'feature_branch_prefix = "{feature_branch_prefix}"')
+    lines.append(f"auto_stash = {'true' if auto_stash else 'false'}")
+    lines.append(f"create_backup_branches = {'true' if create_backup_branches else 'false'}")
+    lines.append("")
+    lines.append("[pr]")
+    lines.append(f"default_draft_pr = {'true' if default_draft_pr else 'false'}")
+    lines.append("")
+    return "\n".join(lines)