docs: add brand hero + logo (WebP, 640px cap)

Wire idlefy-universal hero banner into README.md and docs/index.md;
set the circular logo as the mkdocs Material theme logo + favicon.

Assets shipped as WebP (148 KB total vs 3.2 MB PNG sources): lossy
hero at 1280x853 q=85, lossy logo at 512x512 q=92. Browser support
is ~98% (Chrome since 2010, Safari/iOS 14+, Firefox 65+, Edge 18+);
GitHub README renders inline natively.

Adds docs/assets/extra.css that caps the homepage hero at 640px wide
and centers it. The selector is `.md-typeset img.idlefy-hero` rather
than `.idlefy-hero` because Material's default `.md-typeset img`
rule (specificity 0,1,1) sets `max-width: 100%`, which would beat
a plain class selector (0,1,0). Tagging the element brings us to
(0,1,2) and the cap wins without resorting to !important.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: wowsel

README.md

@@ -1,3 +1,7 @@
+<p align="center">
+  <img src="docs/assets/hero.webp" alt="idlefy-universal — schema-first universal Helm chart for Kubernetes workloads" width="820"/>
+</p>
+
 # idlefy-universal
 
 Universal Helm chart for Kubernetes workloads — typed JSON Schema, agent-native metadata, auto-creation, Gateway API.

docs/assets/extra.css

@@ -0,0 +1,16 @@
+/*
+ * Center and constrain the homepage hero so it scales on mobile.
+ *
+ * Specificity note: Material's `.md-typeset img` (0,1,1) sets
+ * `max-width: 100%`, which beats a plain `.idlefy-hero` (0,1,0)
+ * and ignores our cap. Tagging the selector with the element
+ * keeps us at (0,1,2) and wins without !important.
+ */
+.md-typeset img.idlefy-hero {
+  display: block;
+  margin: 0 auto 1.5rem;
+  max-width: 640px;
+  width: 100%;
+  height: auto;
+  border-radius: 8px;
+}

docs/assets/hero.webp

@@ -4,6 +4,8 @@ hide:
   - toc
 ---
 
+![idlefy-universal — schema-first universal Helm chart for Kubernetes workloads](assets/hero.webp){ .idlefy-hero }
+
 # idlefy-universal
 
 > Schema-driven, agent-native Helm chart for any Kubernetes workload.

docs/assets/logo.webp

@@ -21,6 +21,8 @@ exclude_docs: |
 
 theme:
   name: material
+  logo: assets/logo.webp
+  favicon: assets/logo.webp
   features:
     - navigation.tabs
     - navigation.tabs.sticky
@@ -72,6 +74,9 @@ extra:
     - icon: fontawesome/brands/github
       link: https://github.com/idlefy/idlefy-universal
 
+extra_css:
+  - assets/extra.css
+
 nav:
   - Home: index.md
   - Tutorials: