fix: RSS proxy allowlist + add 9 new positive news feeds (#360)

* fix: add redirect target domains to RSS proxy allowlist

HuffPost and Nature feeds redirect to different hostnames
(chaski.huffpost.com, www.nature.com) that weren't in ALLOWED_DOMAINS,
causing the proxy to reject the redirect and fall through to the
Railway relay (which is currently down).

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

* fix: remove dead RSS feeds and add 9 new positive news sources

Remove Sunny Skyz (old URL dead) and HuffPost Good News (feed discontinued).
Replace with verified working feeds:
- Positive: Upworthy, DailyGood, Good Good Good, GOOD Magazine,
  Sunny Skyz (new URL), The Better India
- Science: Singularity Hub, Human Progress, Greater Good (Berkeley)

Also add redirect target domains (www.nature.com) to proxy allowlist
and remove dead HuffPost domains.

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

* fix: add fallback data for Progress/Renewable panels + expand Breakthroughs sources

World Bank API is intermittent (some indicators time out with 0 bytes).
Both Human Progress and Renewable Energy panels silently returned empty
when API was unavailable and no IndexedDB cache existed.

- Add hardcoded fallback datasets (verified from World Bank, Feb 2026)
  for all 4 progress indicators and renewable energy global/regional data
- Use fallback instead of empty on any API failure or empty response
- Add Singularity Hub, Human Progress, Greater Good (Berkeley) to
  Breakthroughs panel source filter so new science feeds show up

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

api/rss-proxy.js

@@ -247,9 +247,16 @@ const ALLOWED_DOMAINS = [
   'www.positive.news',
   'reasonstobecheerful.world',
   'www.optimistdaily.com',
+  'www.upworthy.com',
+  'www.dailygood.org',
+  'www.goodgoodgood.co',
+  'www.good.is',
   'www.sunnyskyz.com',
-  'www.huffpost.com',
-  'chaski.huffpost.com',
+  'thebetterindia.com',
+  'singularityhub.com',
+  'humanprogress.org',
+  'greatergood.berkeley.edu',
+  'www.onlygoodnewsdaily.com',
   'www.sciencedaily.com',
   'feeds.nature.com',
   'www.nature.com',