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, 42 insertions, 0 deletions

diff --git a/docs/vpp/md-limitations.md b/docs/vpp/md-limitations.md
new file mode 100644
index 00000000..9582347a
--- /dev/null
+++ b/docs/vpp/md-limitations.md
@@ -0,0 +1,42 @@
+---
+lastproofread: '2026-02-17'
+---
+
+(vpp-limitations)=
+
+```{include} /_include/need_improvement.txt
+```
+
+# VPP Dataplane Limitations
+
+VPP Dataplane provides significant performance advantages, but has some
+limitations you should consider.
+
+- **Feature Parity**
+
+  VPP does not support all features available in the Linux kernel dataplane.
+  Some networking features, specific protocols, or services may not be
+  available.
+
+  While VPP supports various interface types similar to the kernel, their
+  capabilities may differ.
+
+- **NIC and Driver Compatibility**
+
+  VyOS currently supports only DPDK drivers for network interfaces.
+  Not all network interface cards are compatible with DPDK drivers.
+
+- **Data Path Limitations**
+
+  If a feature exists only in the kernel dataplane, traffic that uses that
+  feature cannot traverse VPP interfaces. Examples include:
+
+  - Firewall
+  - QoS
+
+  When traffic uses the pure VPP path, it does not reach the kernel, where
+  such features are implemented. Plan how traffic flows through your VyOS
+  instance to ensure it reaches the necessary features.
+
+  VPP provides native alternatives for some features. For example, VPP
+  native ACLs provide basic firewall functionality.