📚 Document branch naming convention

The creating-prs memory described a branch format (issue/... with a
<type>/<short-description> fallback) that does not match actual repo
practice, where issue-driven branches are issue-NNNN. Replace it with
a Branch Naming section: issue-NNNN as primary, descriptive name
without slashes as fallback.

Add the matching public convention to CONTRIBUTING.md under Pull
Requests, which previously defined no branch naming at all.

AI-assisted-by: omen-alpha

.serena/memories/workflow/creating-prs.md

@@ -1,6 +1,12 @@
 # Creating Pull Requests
 
-PR only on explicit request. Branch: issue/feature-specific; fallback `<type>/<short-description>` (`fix/...`, `feat/...`, `refactor/...`, `docs/...`, `chore/...`, `perf/...`).
+PR only on explicit request.
+
+## Branch Naming
+
+- Primary: `issue-NNNN` — one branch per GitHub issue (e.g. `issue-11525`).
+- No issue: free-form descriptive name, dash-separated, no slashes (e.g. `fix-ellipse-icon-typo`, `feat-auto-link-libraries`).
+- If the user already created the branch, use it as-is — never rename.
 
 ## Target Branch
 

CONTRIBUTING.md

@@ -14,6 +14,7 @@ Center](https://help.penpot.app/).
 - [Reporting Bugs](#reporting-bugs)
 - [Pull Requests](#pull-requests)
   - [Workflow](#workflow)
+  - [Branch naming](#branch-naming)
   - [Format](#format)
     - [Title format](#title-format)
     - [Description](#description)
@@ -73,6 +74,18 @@ Advisories](https://github.com/penpot/penpot/security/advisories)
 4. **Format and lint** — run the checks described in
    [Formatting and Linting](#formatting-and-linting) before submitting.
 
+### Branch naming
+
+Branch names are not enforced, but we recommend the following:
+
+- **`issue-NNNN`** — when working from a GitHub issue, name the branch after
+  it (e.g. `issue-11525`). This makes each PR's origin self-evident.
+- Otherwise, use a short, descriptive name with words separated by hyphens
+  and no slashes (e.g. `fix-ellipse-icon-typo`, `feat-auto-link-libraries`).
+
+Since PRs are squash-merged, the branch name does not survive into the
+commit history — what matters is the [PR title](#title-format).
+
 ### Format
 
 #### Title