Add option to specify custom branch name

[patrick91]

Problem

Currently, branch names are always auto-generated from the commit message with no way to override. This can be limiting when:

• The commit message doesn't translate well to a branch name
• User has a specific naming convention
• Multiple commits with similar messages create confusing branch names

Examples from Other Tools

Charcoal:

charcoal create -n my-custom-branch -m "My commit message"

st:

st create my-custom-branch  # Or prompts interactively

Proposed Solution

Add a --name (or -n) flag to the create command:

shortcake create --name my-feature-branch

Implementation Options

Option 1: Flag Only

shortcake create --name custom-branch
# Opens editor, commits, uses 'custom-branch' as name

Option 2: Interactive Fallback

shortcake create
# After commit, show: "Generated branch name: add-new-feature"
# Prompt: "Use this name? [Y/n] (or enter custom name):"

Option 3: Positional Argument

shortcake create [branch-name]
# If provided, use it; otherwise auto-generate

User Stories

• As a developer, I want to use my team's branch naming convention (e.g., feature/TICKET-123-description)
• As a developer, I want to preview the auto-generated name and change it if needed
• As a developer, I want to create branches without committing first (empty branch for future work)

Implementation Notes

Related code: shortcake/cli.py:125-132

Would need to modify the create command to accept an optional name parameter and skip auto-generation if provided.

[patrick91]

Triaged against main at 52da8bd.

Still open. The lower-level _create(...) helper accepts an explicit branch name and has a unit test for that path, but the CLI create(...) command does not expose --name, -n is already used for --no-verify, and branch names are still generated from the commit message except for the empty-slug prompt fallback.

One implementation decision: choose a flag that does not conflict with -n / --no-verify, or decide to change that short option intentionally.