ci: only build when image-affecting files change

Add path filters so the workflow runs only when the Dockerfile, nginx config,
site assets or .dockerignore change. CI-config, Renovate-config and docs
changes (such as a Renovate bump of a CI action) no longer trigger a build or
release. workflow_dispatch is added for manual runs after pipeline changes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/build-and-publish.yml

@@ -1,10 +1,31 @@
 name: Build and publish container
 
+# Only run when files that affect the built image change. Updates to CI
+# config, Renovate config, or docs (e.g. a Renovate bump of the checkout
+# action) do not change the image and so do not trigger a build or release.
+# Use workflow_dispatch to run manually after a pipeline change.
 on:
   push:
     branches: [main]
+    paths:
+      - 'Dockerfile'
+      - 'default.conf'
+      - 'index.html'
+      - 'styles.css'
+      - 'script.js'
+      - 'messages.js'
+      - '.dockerignore'
   pull_request:
     branches: [main]
+    paths:
+      - 'Dockerfile'
+      - 'default.conf'
+      - 'index.html'
+      - 'styles.css'
+      - 'script.js'
+      - 'messages.js'
+      - '.dockerignore'
+  workflow_dispatch:
 
 defaults:
   run:

styles.css

@@ -63,13 +63,10 @@ body {
   padding: 1.5rem;
 }
 
-/* Segmented control: both options joined in one rounded container,
-   with the active segment filled. */
 .theme-toggle {
-  display: inline-flex;
-  border: 2px solid var(--button-bg);
-  border-radius: 999px;
-  overflow: hidden;
+  display: flex;
+  gap: 0.5rem;
+  border: none;
   margin: 0;
   padding: 0;
 }
@@ -78,22 +75,19 @@ body {
   font-family: inherit;
   font-size: 0.9rem;
   font-weight: 600;
-  padding: 0.5rem 1.1rem;
-  border: none;
+  padding: 0.5rem 1rem;
+  border: 2px solid var(--button-bg);
+  border-radius: 999px;
   background: transparent;
   color: var(--text);
   cursor: pointer;
   transition: background 0.2s ease, color 0.2s ease;
 }
 
-/* Divider between the two segments. */
-.theme-button + .theme-button {
-  border-left: 2px solid var(--button-bg);
-}
-
 .theme-button[aria-pressed="true"] {
   background: var(--button-active-bg);
   color: var(--button-active-text);
+  border-color: var(--button-active-bg);
 }
 
 .stage {