chore: add copyright (#8584)

* feat: adding new copyright info on all files

* chore: adding CI

COPYRIGHT_CHECK.md

@@ -0,0 +1,34 @@
+## Copyright check
+
+To verify that all tracked Python files contain the correct copyright header for **Plane Software Inc.** for the year **2023**, run this command from the repository root:
+
+```bash
+addlicense --check -f COPYRIGHT.txt -ignore "**/migrations/**" $(git ls-files '*.py')
+```
+
+#### To Apply Changes
+
+python files
+
+```bash
+addlicense -v -f COPYRIGHT.txt -ignore "**/migrations/**" $(git ls-files '*.py')
+```
+
+ts and tsx files in a specific app
+
+```bash
+addlicense -v -f COPYRIGHT.txt \
+  -ignore "**/*.config.ts" \
+  -ignore "**/*.d.ts" \
+  $(git ls-files 'packages/*.ts')
+```
+
+Note: Please make sure ts command is running on specific folder, running it for the whole mono repo is crashing os processes.
+
+#### Other Options
+
+- **`addlicense -check`**: runs in check-only mode and fails if any file is missing or has an incorrect header.
+- **`-c "Plane Software Inc."`**: sets the copyright holder.
+- **`-f LICENSE.txt`**: uses the contents and format defined in `LICENSE.txt` as the header template.
+- **`-y 2023`**: sets the year in the header.
+- **`$(git ls-files '*.py')`**: restricts the check to Python files tracked in git.