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, 0 insertions, 105 deletions

diff --git a/docs/installation/md-update.md b/docs/installation/md-update.md
deleted file mode 100644
index e8b5f912..00000000
--- a/docs/installation/md-update.md
+++ /dev/null
@@ -1,105 +0,0 @@
----
-lastproofread: '2026-01-26'
----
-
-(update_vyos)=
-
-# Update VyOS
-
-New system images can be added using the {opcmd}`add system image` command.
-This command extracts the image and prompts you to use the current system
-configuration and SSH security keys, allowing the new image to boot with your
-current configuration.
-
-:::{note}
-Only LTS releases are PGP-signed.
-:::
-
-```{opcmd} add system image \<url | path\> | [latest] [vrf name] [username user [password pass]]
-
-Use this command to install a new system image. You can retrieve the
-image from the web (``http://``, ``https://``) or from your local system.
-For example: /tmp/vyos-1.2.3-amd64.iso.
-
-   The ``add system image`` command also supports installing new VyOS versions
-   through an optional VRF. If the URL requires authentication, you can specify
-   an optional username and password on the command line, which will be passed
-   as "Basic-Auth" to the server.
-```
-
-If there isn't enough free disk space, the installation will be canceled.
-To delete images, use the {opcmd}`delete system image` command.
-
-
-VyOS associates configuration with each image, and each image has its own
-unique configuration copy. This differs from traditional network routers where
-the configuration is shared across all images.
-
-
-:::{note}
-If you have personal files such as scripts that you want to preserve
-during the upgrade, store them in `/config` since this directory is always
-copied to newly installed images.
-:::
-
-
-You can access files from a previous installation and copy them to your
-current image if they were stored in the `/config` directory. Use the
-{opcmd}`copy` command to do this. For example, to copy `/config/config.boot`
-from the VyOS `1.2.1` image, run:
-
-```none
-copy file 1.2.1://config/config.boot to /tmp/config.boot.1.2.1
-```
-
-
-#### Example
-
-```none
-vyos@vyos:~$ add system image https://s3.amazonaws.com/s3-us.vyos.io/rolling/current/vyos-1.4-rolling-202201120317-amd64.iso
-Trying to fetch ISO file from https://s3.amazonaws.com/s3-us.vyos.io/rolling/current/vyos-1.4-rolling-202201120317-amd64.iso
-  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
-                                 Dload  Upload   Total   Spent    Left  Speed
-100  338M  100  338M    0     0  3837k      0  0:01:30  0:01:30 --:--:-- 3929k
-ISO download succeeded.
-Checking for digital signature file...
-  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
-                                 Dload  Upload   Total   Spent    Left  Speed
-  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
-curl: (22) The requested URL returned error: 404 Not Found
-
-Unable to fetch digital signature file.
-Do you want to continue without signature check? (yes/no) [yes]
-Checking MD5 checksums of files on the ISO image...OK.
-Done!
-
-What would you like to name this image? [vyos-1.3-rolling-201912201452]:
-
-OK.  This image will be named: vyos-1.3-rolling-201912201452
-```
-
-You can use `latest` option. It loads the latest available Rolling release.
-
-```none
-vyos@vyos:~$ add system image latest
-```
-
-:::{note}
-To use the `latest` option, "system update-check url" must be
-configured appropriately for your installed release.
-
-For updates to the Rolling Release for AMD64, the following URL may be
-used:
-
-<https://raw.githubusercontent.com/vyos/vyos-nightly-build/refs/heads/current/version.json>
-:::
-
-:::{hint}
-You can access the latest Rolling Release for AMD64 from a web
-browser at:
-
-<https://vyos.net/get/nightly-builds/>
-:::
-
-After rebooting, verify the version you're running using the
-{opcmd}`show version` command.