feat(v0.5.1-prep): expand Quick Stations 8 → 14

Adds 6 more SomaFM channels to the NewTab Quick Stations chip row.
Was reading sparse with only 8; the row had space for more. Selections
broaden genre coverage and add two on-brand picks:

  +  defcon       DEF CON Radio       (electronic / hacker culture)
  +  beatblender  Beat Blender        (electronic / breakbeat)
  +  bootliquor   Boot Liquor         (americana / outlaw country)
  +  u80s         Underground 80s     (80s indie / synthwave)
  +  bagel        BAGeL Radio         (indie / alt-rock)
  +  thistle      ThistleRadio        (celtic / folk — Dublin nod)

Total chip count: 8 → 14. No code change other than the QUICK_IDS
array. The render loop already drops any ID that's missing from
SomaFM's channels.json catalogue, so if a slug changes upstream
it just disappears silently.

DEF CON Radio = David's personal favourite (used as the test
station throughout v0.3.0 development). ThistleRadio = Irish-built
extension nodding to Celtic folk. Both feel right for the demographic
this product serves.

src/newtab/newtab.js

@@ -57,15 +57,26 @@ const CATALOGUE_TTL_MS = 6 * 60 * 60 * 1000;
 
 // Quick-pick stations. These are the SomaFM ids most people start with.
 // If the catalogue is missing any (rare), they're just dropped silently.
+//
+// Layout: 14 stations across roughly chill / ambient / indie / lounge /
+// space / electronic / americana / 80s / alt-rock / celtic — broader
+// genre coverage than the v0.4.0 list, plus DEF CON Radio (the on-brand
+// cybersecurity pick) and ThistleRadio (the Dublin-built Irish nod).
 const QUICK_IDS = [
-  'groovesalad',
-  'dronezone',
-  'indiepop',
-  'secretagent',
-  'spacestation',
-  'lush',
-  'deepspaceone',
-  'fluid',
+  'groovesalad',     // chill / electronic
+  'dronezone',       // ambient
+  'indiepop',        // indie pop rocks
+  'secretagent',     // lounge / spy
+  'spacestation',    // ambient / space
+  'lush',            // vocal / chill
+  'deepspaceone',    // ambient
+  'fluid',           // electronic
+  'defcon',          // electronic / hacker culture (DEF CON Radio)
+  'beatblender',     // electronic / breakbeat
+  'bootliquor',      // americana / outlaw country
+  'u80s',            // 80s indie / synthwave (Underground 80s)
+  'bagel',           // indie / alt-rock (BAGeL Radio)
+  'thistle',         // celtic / folk (ThistleRadio)
 ];
 
 let stations = [];