Add mobile responsiveness to ToolsnToys hub pages; fix table overflow in guides

Add 680px breakpoint to toolsntoys, foss-tools, guides, jl-early-tools:
header stacks, stats bar collapses to 2-col, sidebar/content grid stacks.
Fix table overflow in 3 guide pages: move overflow-x:hidden from body to
.guide-wrap so .guide-table-wrap scroll containers work on mobile Safari.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ToolsnToys/appimage-installation-guide.html

@@ -32,9 +32,7 @@
     background: var(--bg-deep);
     color: var(--text-main);
     font-family: 'Rambla', sans-serif;
-    min-height: 100vh;
-    overflow-x: hidden;
-  }
+    min-height: 100vh;}
 
   body::before {
     content: '';
@@ -90,7 +88,7 @@
 
   #embers { position: fixed; inset: 0; pointer-events: none; z-index: 3; }
 
-  .guide-wrap {
+  .guide-wrap { overflow-x: hidden;
     position: relative;
     z-index: 1;
     display: grid;