feat: authenticate Renovate to the code.emmathe.dev container registry

Add a docker hostRule so Renovate can read/update digests for private images
(dlr, docs-site) pinned in the Terraform repo. Token via RENOVATE_REGISTRY_TOKEN env.

config.js

@@ -11,6 +11,18 @@ module.exports = {
     "minimumReleaseAge": "3 days",
     "labels": ["dependencies"],
     "reviewers": ["lyrathorpe"],
+    "hostRules": [
+        {
+            // Authenticate to the code.emmathe.dev container registry so Renovate can read and
+            // update digests for private images (e.g. code.emmathe.dev/lyrathorpe/whyisthedlrshut.today
+            // and .../docs-site, pinned in the Terraform repo). Token = a Gitea PAT with read:package;
+            // supplied via the RENOVATE_REGISTRY_TOKEN environment variable on the bot.
+            "matchHost": "code.emmathe.dev",
+            "hostType": "docker",
+            "username": "renovate-bot",
+            "password": process.env.RENOVATE_REGISTRY_TOKEN
+        }
+    ],
     "prHourlyLimit": 10,
     "prConcurrentLimit": 10,
     "branchConcurrentLimit": 10,