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, 16 insertions, 0 deletions

diff --git a/docs/configexamples/md-firewall.md b/docs/configexamples/md-firewall.md
new file mode 100644
index 00000000..5d170511
--- /dev/null
+++ b/docs/configexamples/md-firewall.md
@@ -0,0 +1,16 @@
+---
+lastproofread: '2024-09-11'
+---
+
+# Firewall Examples
+
+This section contains examples of firewall configurations for various
+deployments.
+
+```{toctree}
+:maxdepth: 2
+
+fwall-and-vrf
+fwall-and-bridge
+zone-policy
+```