Add the talk to the landing showcase; point Atlas at its subdomain

- Landing 'From hackerspace.sh' showcase: add a 'Hacking Your Hackerspace'
  tile (07 projects) linking the deck on hack.build, with a new HackBuildIcon
  (the brand's pink open-end wrench).
- Point the Atlas tile at https://atlas.hackerspace.sh (now live) instead of
  the old internal /atlas route.
- Use the same hack.build wrench for the talk card on the Resources page.

components/landing/resource-showcase.tsx

@@ -1,17 +1,19 @@
 import Link from 'next/link'
 import { AtlasLogo } from '@/components/resources/atlas-logo'
-import { CubeIcon, TraceIcon, SpaceIcon, GridIcon, KeyIcon } from '@/components/resources/icons'
+import { CubeIcon, TraceIcon, SpaceIcon, GridIcon, KeyIcon, HackBuildIcon } from '@/components/resources/icons'
 
-// The six hackerspace.sh research/game projects, shown as a single row of
-// square tiles at the foot of the landing page. Internal routes use next/link;
-// the interactive learner is an external app.
+// The hackerspace.sh research/game projects, shown as a single row of square
+// tiles at the foot of the landing page. Internal routes use next/link;
+// external apps (the Atlas subdomain, the interactive learner, the talk) open
+// in a new tab.
 const RESOURCES = [
-  { title: 'Atlas', href: '/atlas', external: false, visual: <AtlasLogo /> },
+  { title: 'Atlas', href: 'https://atlas.hackerspace.sh', external: true, visual: <AtlasLogo /> },
   { title: 'Space After Dark', href: '/space-after-dark', external: false, visual: <CubeIcon /> },
   { title: 'Proposal Duel', href: '/proposal-duel', external: false, visual: <TraceIcon /> },
   { title: 'The Hackerspace Game', href: '/zine', external: false, visual: <SpaceIcon /> },
   { title: 'Interactive Learner', href: 'https://hackerspacegame.netlify.app/', external: true, visual: <GridIcon /> },
   { title: 'Governance in a Box', href: '/governance', external: false, visual: <KeyIcon /> },
+  { title: 'Hacking Your Hackerspace', href: 'https://hack.build/hacking-your-hackerspace.html', external: true, visual: <HackBuildIcon /> },
 ]
 
 export function ResourceShowcase() {
@@ -20,7 +22,7 @@ export function ResourceShowcase() {
       <div className="landing-container">
         <div className="landing-section-head">
           <span className="landing-section-label">From hackerspace.sh</span>
-          <span className="landing-section-note">06 projects</span>
+          <span className="landing-section-note">07 projects</span>
         </div>
         <div className="landing-showcase">
           {RESOURCES.map(r =>