Web UI polish: thumbnail-hover preview, white thumbnail selection, Themes bullet list; global Scryfall image retry (thumbs+previews) with fallbacks and cache-bust; standardized data-card-name. Deck Summary alignment overhaul (count//name/owned grid, tabular numerals, inset highlight, tooltips, starts under header). Added diagnostics (health + logs pages, error pages, request-id propagation), global HTMX error toasts, and docs updates. Update DOCKER guide and add run-web scripts. Update CHANGELOG and release notes template.

code/web/templates/errors/404.html

@@ -0,0 +1,13 @@
+{% extends "base.html" %}
+{% block content %}
+<section>
+  <h2>Page not found</h2>
+  <p>The page you requested could not be found.</p>
+  <p class="muted">Request ID: <code>{{ request_id or request.state.request_id }}</code></p>
+  <p><a class="btn" href="/">Go home</a></p>
+  <details>
+    <summary>Details</summary>
+    <pre>Status: {{ status }}
+Path: {{ request.url.path }}</pre>
+  </details>
+{% endblock %}

code/web/templates/errors/4xx.html

@@ -0,0 +1,13 @@
+{% extends "base.html" %}
+{% block content %}
+<section>
+  <h2>Error {{ status }}</h2>
+  <p>{{ detail }}</p>
+  <p class="muted">Request ID: <code>{{ request_id or request.state.request_id }}</code></p>
+  <p><a class="btn" href="/">Go home</a></p>
+  <details>
+    <summary>Details</summary>
+    <pre>Status: {{ status }}
+Path: {{ request.url.path }}</pre>
+  </details>
+{% endblock %}

code/web/templates/errors/500.html

@@ -0,0 +1,8 @@
+{% extends "base.html" %}
+{% block content %}
+<section>
+  <h2>Internal Server Error</h2>
+  <p>Something went wrong.</p>
+  <p class="muted">Request ID: <code>{{ request_id or request.state.request_id }}</code></p>
+  <p><a class="btn" href="/">Go home</a></p>
+{% endblock %}