feat: track ubuntu 26.04 (resolute) on main (#38)

Bump base image to ubuntu:resolute-20260413 and publish images tagged
resolute, 26.04, and latest from this branch. The noble branch
continues to track 24.04.

Renovate is configured with baseBranches so each branch receives only
the updates that match its release line: resolute-* on main and
noble-* on noble.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: gilesknap

.github/workflows/ci.yml

@@ -115,7 +115,8 @@ jobs:
           tags: |
             type=ref,event=tag
             type=raw,value=latest
-            type=raw,value=noble
+            type=raw,value=resolute
+            type=raw,value=26.04
 
       - name: Log in to GitHub Docker Registry
         uses: docker/login-action@v4

Dockerfile

@@ -1,6 +1,6 @@
 # The devcontainer should use the developer target and run as root with podman
 # or docker with user namespaces.
-FROM ubuntu:noble-20260410
+FROM ubuntu:resolute-20260413
 
 # Add any system dependencies for the developer/build environment here
 RUN apt-get update && \

renovate.json

@@ -2,5 +2,21 @@
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": [
     "config:recommended"
+  ],
+  "baseBranches": [
+    "main",
+    "noble"
+  ],
+  "packageRules": [
+    {
+      "matchBaseBranches": ["main"],
+      "matchDepNames": ["ubuntu"],
+      "allowedVersions": "/^resolute(-.*)?$/"
+    },
+    {
+      "matchBaseBranches": ["noble"],
+      "matchDepNames": ["ubuntu"],
+      "allowedVersions": "/^noble(-.*)?$/"
+    }
   ]
 }