feat: flip swap mechanism — MD as primary, RST as override (Phase 1)

This is the first of three phases inverting the per-page swap mechanism
so MD becomes the canonical primary and RST becomes the rare override.

Phase 1 — file renames + conf.py exclude_patterns flip only:
- Rename docs/**/md-<stem>.md to docs/**/<stem>.md (drop md- prefix)
  for all 254 stems previously listed in docs/_swap.txt
- Rename docs/**/<stem>.rst to docs/**/rst-<stem>.rst (add rst- prefix)
  for the same 254 stems
- Repurpose docs/_swap.txt as docs/_rst_overrides.txt; initially empty
  comment-only since no pages need the RST fallback right now
- conf.py exclude_patterns flipped: rst-*.rst is now excluded by default
  instead of md-*.md
- conf.py runtime-artifact references updated to _rst_override_state.json
  and _md_exclude.txt (Phase 2 will rewrite swap_sources.py to produce
  these names; for now no swap script runs because overrides list is empty)

Phase 2 (next commit on this branch) will rewrite scripts/swap_sources.py
with inverted rename direction, delete scripts/import_myst.py + tests, and
update tests/test_swap_sources.py for the new semantics.

Phase 3 will be the cleanup pass and ready-for-review flip.

Generated by robots https://vyos.io

1 files changed, 65 insertions, 0 deletions

diff --git a/docs/configuration/interfaces/rst-loopback.rst b/docs/configuration/interfaces/rst-loopback.rst
new file mode 100644
index 00000000..68158111
--- /dev/null
+++ b/docs/configuration/interfaces/rst-loopback.rst
@@ -0,0 +1,65 @@
+:lastproofread: 2026-01-23
+
+.. _loopback-interface:
+
+########
+Loopback
+########
+
+The loopback interface is a virtual, software-based network interface. All 
+traffic sent to it loops back and only targets services on the local host.
+
+.. note:: Only one loopback ``lo`` interface is allowed per operating system. 
+   If you require multiple virtual interfaces, use the :ref:`dummy-interface`
+   interface type.
+
+*************
+Configuration
+*************
+
+Common interface configuration
+==============================
+
+.. cmdinclude:: /_include/interface-address.txt
+   :var0: loopback
+   :var1: lo
+
+.. cmdinclude:: /_include/interface-description.txt
+   :var0: loopback
+   :var1: lo
+
+*********
+Operation
+*********
+
+.. opcmd:: show interfaces loopback
+
+   Show brief interface information.
+
+   .. code-block:: none
+
+     vyos@vyos:~$ show interfaces loopback
+     Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
+     Interface        IP Address                        S/L  Description
+     ---------        ----------                        ---  -----------
+     lo               127.0.0.1/8                       u/u
+                      ::1/128
+
+.. opcmd:: show interfaces loopback lo
+
+   Show detailed interface information.
+
+   .. code-block:: none
+
+     vyos@vyos:~$ show interfaces loopback lo
+     lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
+         link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
+         inet 127.0.0.1/8 scope host lo
+            valid_lft forever preferred_lft forever
+         inet6 ::1/128 scope host
+            valid_lft forever preferred_lft forever
+
+         RX:  bytes    packets     errors    dropped    overrun      mcast
+                300          6          0          0          0          0
+         TX:  bytes    packets     errors    dropped    carrier collisions
+                300          6          0          0          0          0