Adds non-repo bootstrap and publish flows

### Added
- Non-repository startup flow offering init-only or init+publish paths.
- Provider selection for publishing (GitHub via CLI, Gitea via HTTPS API).
- Gitea repository creation and initial push over HTTPS with configurable base URL, owner, and token defaults.
- Root README and documentation updates describing bootstrap flow and environment variables.

doc/usage.md

@@ -5,6 +5,8 @@
 - Linux or Unix-like terminal environment with curses support.
 - Python 3 interpreter available as `python3`.
 - Git installed and available in `PATH`.
+- GitHub CLI `gh` installed and authenticated for GitHub repository creation. If using Gitea see below.
+- Gitea API token for Gitea repository creation (read/write permissions for repository and organization) over HTTPS.
 
 ## Installation
 
@@ -19,11 +21,29 @@
 
 ## Running
 
-- Enter any Git repository and run:
+- Run from any project directory:
   ```bash
   gtui
   ```
 
+## Non-Repository Bootstrap Flow
+
+- If the current directory is not a Git repository, `git-tui` offers setup actions:
+  - Initialize repository only.
+  - Initialize and publish to a new remote repository.
+- Initialize and publish flow:
+  - Chooses publishing provider: GitHub or Gitea.
+  - Initializes a local Git repository.
+  - Stages all current files.
+  - Creates an initial commit.
+  - GitHub option creates and pushes via `gh repo create --source=. --remote=origin --push`.
+  - Gitea option creates via HTTPS API, configures `origin`, and pushes with HTTPS authentication using the provided token.
+- Optional Gitea environment variables:
+  - `GITEA_URL` or `GITEA_BASE_URL` for instance URL default.
+  - `GITEA_OWNER` for default owner or organization.
+  - `GITEA_TOKEN` or `GITEA_ACCESS_TOKEN` for API token default.
+- Git credential prompts are disabled inside `git-tui`; authentication issues are reported in the UI instead of opening an interactive terminal prompt.
+
 ## Key Commands in UI
 
 - Main menu: