docs: rebrand Certifai -> Prüfwerk (user-facing name)

The product is renamed Certifai -> Prüfwerk. This changes only the user-facing
brand text in the documentation (docs/**, VitePress title/name). It does NOT
touch functional identifiers that happen to contain "certifai" (the Docker
network, Keycloak realm/client, Harbor image project, the compliance-* crate
names, or the repo name) — those are infra-coupled and need a separate,
coordinated migration.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EgxGHn22YEfQz5fLHSHkLv

docs/reference/plc-runtimes.md

@@ -4,9 +4,9 @@ A soft PLC is a **SoC + Linux + a software runtime + an IEC 61131-3 control app*
 (see [PLC / SPS Projects](/guide/plc)).
 The **runtime** is what defines the device — it provides the IEC engine, the
 Modbus / OPC UA / EtherNet/IP servers, and the WebVisu. This page tracks the
-runtime ecosystems Certifai may encounter.
+runtime ecosystems Prüfwerk may encounter.
 
-We do **not** aim to support every runtime up front. Certifai supports the
+We do **not** aim to support every runtime up front. Prüfwerk supports the
 **CODESYS family** today; everything else is a **watch-list** — when a customer
 shows up using one, we add the parser/support for it then. The dynamic OT probe
 (Modbus / OPC UA / EtherNet/IP) is **vendor-agnostic** and works regardless of