fix(docker): build piguard images locally from public source

The published GHCR packages for go-prompt-injection-guard are private, causing 'unauthorized' pull errors. Switch the compose file to build both the daemon and gateway images locally from the public GitHub repo at v1.0.0. Update docker/README.md to explain the local build behavior.

Author: jkyberneees

docker/README.md

@@ -275,6 +275,12 @@ Both bundled configs (`config.restricted.json` and `config.godmode.json`) set:
 The sidecar is internal-only (no host port) and reachable only by the odek containers
 over the compose network at `http://piguard-gateway:8080`.
 
+The `piguard` and `piguard-gateway` images are **built locally** from the public
+go-prompt-injection-guard source repository (the GHCR packages are private). The first
+`docker compose --profile ... up --build` clones the guard repo and compiles both
+binaries; after that, the cached `piguard:local` / `piguard-gateway:local` images are
+reused.
+
 ### One-time model download
 
 The PIGuard model (~735 MB) is **not** baked into the image — it is exported once and

docker/docker-compose.yml

@@ -163,7 +163,13 @@ services:
   # its existing HTTP-based piguard client without sharing a socket volume.
   piguard:
     profiles: ["restricted", "godmode", "telegram-restricted", "telegram-godmode"]
-    image: ghcr.io/backendstack21/go-prompt-injection-guard:v1.0.0
+    # GHCR packages for this repo are private, so we build the daemon image locally
+    # from the public source. The first build clones the repo and compiles the
+    # binary; subsequent starts reuse the cached image.
+    build:
+      context: https://github.com/BackendStack21/go-prompt-injection-guard.git#v1.0.0
+      dockerfile: Dockerfile
+    image: piguard:local
     command:
       - "--socket=/run/piguard/piguard.sock"
       - "--model-dir=/models"
@@ -182,7 +188,11 @@ services:
 
   piguard-gateway:
     profiles: ["restricted", "godmode", "telegram-restricted", "telegram-godmode"]
-    image: ghcr.io/backendstack21/go-prompt-injection-guard-gateway:v1.0.0
+    # Built locally from the public guard repo source (GHCR packages are private).
+    build:
+      context: https://github.com/BackendStack21/go-prompt-injection-guard.git#v1.0.0
+      dockerfile: examples/http-gateway/Dockerfile
+    image: piguard-gateway:local
     command: ["--addr=:8080", "--socket=/run/piguard/piguard.sock"]
     volumes:
       - piguard-sock:/run/piguard