docs(reference/nix-daemon-protocol): migrate

This moves the daemon protocol reference to the "Reference" section in
our new docs.

It also updates them a bit, we now use `{{< relref "path/to/file.md" >}}`
to refer to other files, and fixes the (previously broken) references
in handshake.md.

Change-Id: I114e40622dc504e7a5f75946895900e797a1e722
Reviewed-on: https://cl.snix.dev/c/snix/+/30273
Autosubmit: Florian Klink <flokli@flokli.de>
Tested-by: besadii
Reviewed-by: Brian Olsen <brian@maven-group.org>

web/content/docs/reference/nix-daemon-protocol/handshake.md

@@ -0,0 +1,49 @@
+---
+title: Handshake
+slug: handshake
+description: ""
+summary: ""
+date: 2025-03-24T13:10:37+02:00
+lastmod: 2025-03-24T13:10:37+02:00
+draft: false
+weight: 51
+toc: true
+---
+
+When connecting, the handshake sequence documented below must be performed, so
+client and server can agree on a protocol version to use and exchange some
+parameters.
+
+## client -> server
+- 0x6e697863 :: [Int](#se-Int) (hardcoded, 'nixc' in ASCII)
+
+## client <- server
+- 0x6478696f :: [Int](#se-Int) (hardcoded, 'dxio' in ASCII)
+- protocolVersion :: [Int](#se-Int)
+
+## client -> server
+- clientVersion :: [Int](#se-Int)
+
+### If clientVersion is 1.14 or later
+- sendCpu :: [Bool](#se-Bool) (hardcoded to false in client)
+#### If sendCpu is true
+- cpuAffinity :: [Int](#se-Int) (obsolete and ignored)
+
+### If clientVersion is 1.11 or later
+- reserveSpace :: [Bool](#se-Bool) (obsolete, ignored and set to false)
+
+
+## client <- server
+
+### If clientVersion is 1.33 or later
+- nixVersion :: String
+
+### If clientVersion is 1.35 or later
+- trusted :: OptTrusted
+
+## client <- server
+- send logs
+- [operation]({{< relref "operations.md" >}}) :: [Int](#se-Int)
+
+[se-Int]: {{< relref "serialization.md" >}}#int
+[se-Bool]: {{< relref "serialization.md" >}}#bool