Add PR workflow skill for AI agents

Documents that PRs should target version branches (e.g., 1.8.x)
instead of main, helping AI agents follow the correct workflow.

.claude/skills/pr-workflow.md

@@ -0,0 +1,31 @@
+# PR Workflow for Appwrite
+
+## Branch Targeting
+
+**Important:** Appwrite does NOT use `main` as the primary development branch.
+
+PRs should target the **current version branch** (e.g., `1.8.x`, `1.9.x`), not `main`.
+
+### How to determine the correct target branch
+
+1. Check which version branch you're currently on: `git branch --show-current`
+2. Look for branches matching the pattern `X.Y.x` (e.g., `1.8.x`, `1.9.x`)
+3. The current active development branch is typically the highest version number with the `.x` suffix
+
+### When creating PRs
+
+Always use the version branch as the base:
+
+```bash
+# Correct - targets the version branch
+gh pr create --base 1.8.x --title "Your PR title" --body "..."
+
+# Wrong - do not target main
+gh pr create --base main ...
+```
+
+### Branch naming convention
+
+- `X.Y.x` branches (e.g., `1.8.x`) - Active development branches for each minor version
+- `main` - Not used for regular PRs; reserved for release management
+- Feature branches should be created from and merged back into the current version branch