refactor(swap): rename imported .md files to md- prefix for swap mechanism

Restore the canary file naming convention that swap_sources.py expects:
the imported MyST pages now live as docs/<dir>/md-<name>.md alongside
the existing docs/<dir>/<name>.rst, so swap_sources.py --swap can rename
them into place at build time.

- 254 .md files renamed (every page with a matching .rst counterpart)
- 2 MyST-only pages left at their final names (no .rst exists, no swap
  needed): docs/copyright.md, docs/automation/terraform/terraformvyos.md

All 114 stems listed in docs/_swap.txt now have a corresponding
md-<name>.md source file ready to swap in.

🤖 Generated by [robots](https://vyos.io)

1 files changed, 0 insertions, 45 deletions

diff --git a/docs/contributing/cla.md b/docs/contributing/cla.md
deleted file mode 100644
index 01323111..00000000
--- a/docs/contributing/cla.md
+++ /dev/null
@@ -1,45 +0,0 @@
----
-lastproofread: '2025-12-05'
----
-
-(cla)=
-
-# Contributor License Agreement
-
-Before we can accept your contributions to VyOS, you must sign a **Contributor
-License Agreement (CLA)**.
-
-This is a standard open-source practice that protects both you and the project.
-
-The process is straightforward and fully automated:
-
-1. **Review the CLA document**
-
-   Find the CLA text in our
-   [GitHub repository](https://github.com/vyos/vyos-cla-signatures/).
-
-2. **Submit a pull request**
-
-   When you open a pull request, a CLA bot automatically checks whether all
-   commit authors have signed the CLA.
-
-3. **Follow the bot's instructions**
-
-   If the CLA has not been signed, the bot leaves a comment with instructions.
-   Reply to that comment with the suggested text to sign the CLA.
-
-4. **Wait for confirmation**
-
-   The CLA bot verifies your response and updates the pull request status.
-   Once all commit authors have signed, the bot confirms that the CLA
-   requirement is met and unlocks the pull request for merging.
-
-:::{note}
-Each commit author must sign the CLA.
-
-If your pull request includes commits from multiple contributors, each one
-must sign the CLA before the pull request can be accepted.
-:::
-
-Once you sign the CLA, it remains valid for all your past and future
-contributions to VyOS under the same GitHub identity.