Bump version to 2026.4.0 (#1001)

* Bump version to 2026.4.0

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add PR guidelines to copilot-instructions.md

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bschnurr

.github/copilot-instructions.md

@@ -3,3 +3,9 @@
 ## Learnings
 
 -   Always use `run.executable` (the actual Python binary path) instead of `activatedRun.executable` for interpreter identification in `getInterpreterDetails`, `getSettingsPythonPath`, and `getExecutableCommand`. `activatedRun.executable` may be a wrapper command (e.g. `pixi run python`) set by environment managers like pixi or conda, which breaks the debugger if used as a replacement for the binary. (1)
+
+## Pull Request Guidelines
+
+- Every PR must have at least one label (e.g., `debt`, `bug`, `feature`). The "Ensure Required Labels" status check will block merging without one.
+- Always enable auto-merge (squash) on PRs after creating them: `gh pr merge <number> --repo microsoft/vscode-python-debugger --squash --auto`
+- PRs require approval from someone other than the last pusher before merging.

package.json

@@ -2,7 +2,7 @@
     "name": "debugpy",
     "displayName": "Python Debugger",
     "description": "Python Debugger extension using debugpy.",
-    "version": "2026.3.0-dev",
+    "version": "2026.4.0",
     "publisher": "ms-python",
     "enabledApiProposals": [
         "portsAttributes",