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, 36 insertions, 0 deletions

diff --git a/docs/troubleshooting/md-interfaces.md b/docs/troubleshooting/md-interfaces.md
new file mode 100644
index 00000000..553cbf90
--- /dev/null
+++ b/docs/troubleshooting/md-interfaces.md
@@ -0,0 +1,36 @@
+# Interface Names
+
+If you find the names of your interfaces have changed, this could be because
+your MAC addresses have changed.
+
+- For example, you have a VyOS VM with 4 Ethernet interfaces named
+  eth0, eth1, eth2 and eth3. Then, you migrate your VyOS VM to a different
+  host and find your interfaces now are eth4, eth5, eth6 and eth7.
+
+  One way to fix this issue **taking control of the MAC addresses** is:
+
+  Log into VyOS and run this command to display your interface settings.
+
+  ```none
+  show interfaces detail
+  ```
+
+  Take note of MAC addresses.
+
+  Now, in order to update a MAC address in the configuration, run this command
+  specifying the interface name and MAC address you want.
+
+  ```none
+  set interfaces ethernet eth0 hw-id 00:0c:29:da:a4:fe
+  ```
+
+  If it is a VM, go into the settings of the host and set the MAC address to
+  the settings found in the config.boot file. You can also set the MAC to
+  static if the host allows so.
+
+- Another example could be when cloning VyOS VMs in GNS3 and you get into the
+  same issue: interface names have changed.
+
+  And **a more generic way to fix it** is just deleting every MAC address at
+  the configuration file of the cloned machine. They will be correctly
+  regenerated automatically.