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, 59 insertions, 0 deletions

diff --git a/docs/configuration/system/console.md b/docs/configuration/system/console.md
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+(serial-console)=
+
+# Serial Console
+
+For the average user a serial console has no advantage over a console offered
+by a directly attached keyboard and screen. Serial consoles are much slower,
+taking up to a second to fill a 80 column by 24 line screen. Serial consoles
+generally only support non-proportional ASCII text, with limited support for
+languages other than English.
+
+There are some scenarios where serial consoles are useful. System administration
+of remote computers is usually done using {ref}`ssh`, but there are times when
+access to the console is the only way to diagnose and correct software failures.
+Major upgrades to the installed distribution may also require console access.
+
+```{cfgcmd} set system console device \<device\>
+
+Defines the specified device as a system console. Available console devices
+can be (see completion helper):
+* ``ttySN`` - Serial device name
+* ``ttyAMAN``- Serial device name for some arm64 systems
+* ``ttyUSBX`` - USB Serial device name
+* ``hvc0`` - Xen console
+```
+
+```{cfgcmd} set system console device \<device\> kernel
+
+When set, the selected serial console is used as the kernel boot console.
+When removed, the kernel boot console falls back to tty0.
+
+:::{note}
+Only one serial console can carry the ``kernel`` option.
+When VyOS is installed via serial console, this option is set automatically
+for the serial interface used during installation; usually ``ttyS0`` or
+``ttyAMA0``.
+:::
+```
+
+```{cfgcmd} set system console device \<device\> speed \<speed\>
+
+The speed (baudrate) of the console device. Supported values are:
+* ``1200`` - 1200 bps
+* ``2400`` - 2400 bps
+* ``4800`` - 4800 bps
+* ``9600`` - 9600 bps
+* ``19200`` - 19,200 bps
+* ``38400`` - 38,400 bps (default for Xen console)
+* ``57600`` - 57,600 bps
+* ``115200`` - 115,200 bps (default for serial console)
+
+:::{note}
+If you use USB to serial converters for connecting to your VyOS
+appliance please note that most of them use software emulation without flow
+control. This means you should start with a common baud rate (most likely
+9600 baud) as otherwise you probably can not connect to the device using
+high speed baud rates as your serial converter simply can not process this
+data rate.
+:::
+```
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