docs: Add general Sentry branch naming convention (#17113)

## DESCRIBE YOUR PR

Add a dedicated engineering practices page for the general Sentry branch
naming convention: `<username>/<type>/<short-description>`.

This is separate from the SDK-specific convention (which omits the
username prefix). The general convention includes:

- Username prefix (GitHub username)
- Type matching existing commit message types
- Kebab-case short description

## IS YOUR CHANGE URGENT?

Help us prioritize incoming PRs by letting us know when the change needs
to go live.
- [ ] Urgent deadline (GA date, etc.):
- [ ] Other deadline:
- [x] None: Not urgent, can wait up to 1 week+

## SLA

- Teamwork makes the dream work, so please add a reviewer to your PRs.
- Please give the docs team up to 1 week to review your PR unless you've
added an urgent due date to it.
Thanks in advance for your help!

## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [ ] Checked Vercel preview for correctness, including links
- [ ] PR was reviewed and approved by any necessary SMEs (subject matter
experts)
- [ ] PR was reviewed and approved by a member of the [Sentry docs
team](https://github.com/orgs/getsentry/teams/docs)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: priscilawebdev

develop-docs/engineering-practices/branch-naming.mdx

@@ -0,0 +1,15 @@
+---
+title: Branch Naming
+description: General branch naming convention for Sentry repositories.
+sidebar_order: 11
+---
+
+### Format
+
+Use the format `<username>/<type>/<short-description>`:
+
+- **username**: your GitHub username
+- **type**: one of `feat`, `fix`, `ref`, `perf`, `docs`, `test`, `ci`, `build`, `chore`, `style`, `meta`, `license`
+- **short-description**: what the change is about, in kebab-case
+
+For example: `johndoe/feat/add-resolve-action` or `johndoe/fix/empty-reference-handling`.