feat: clickable source links in synthesis (no raw URLs)

Every cited source — X handles, subreddits, publications, YouTube channels,
Polymarket markets — now renders as a blue CMD-clickable markdown link in the
terminal. Raw URL strings remain forbidden everywhere in the output.

The old rule "NEVER paste raw URLs" blocked both raw URLs and links. Claude
Code renders CommonMark [text](url) as hyperlinks (URL hidden), so the new
rule is: "every link must be [text](url), never a raw URL string". Plain text
is the fallback only when the raw research dump has no URL for a source.

Changes:
- SKILL.md: invert URL formatting rule; update narrative / KEY PATTERNS /
  RECOMMENDATIONS / stats-block templates; retire the "I have all the links...
  Just ask." closer (it's now inline); add two new PRE-PRESENT SELF-CHECK
  items (no raw http/https strings, no broken empty links).
- README.md: note the clickable-links capability in the "How it works" list.
- release-notes.md: 2026-04-20 entry crediting @jay_k and @photomatt.

No Python changes — the raw research dump already carries URLs per item;
this is synthesis-side formatting only. No breaking changes to the engine,
the schema, or the CLI flags.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -209,6 +209,7 @@ These platforms don't have relationships with each other. X doesn't know what Re
 2. **The agent resolves who matters.** Finds X handles (including founders), GitHub repos, subreddits, TikTok hashtags, YouTube channels. For "Kanye West" it knows r/hiphopheads, @kanyewest, and "bully review" on YouTube. For "OpenClaw" it resolves openclaw/openclaw on GitHub and fetches live star counts.
 3. **All sources searched in parallel.** Multi-query expansion. Results scored by engagement, relevance, freshness.
 4. **The depth nobody else has.** Full YouTube transcripts from reaction videos. Top Reddit comments with upvote counts. TikTok captions. Polymarket odds. Not just titles and links.
+   Every cited source is a blue CMD-clickable link in the terminal (X handles, subreddits, publications). No raw URL strings — clean text, one click to the source.
 5. **Same story, merged.** Wireless Festival announced on Reddit, discussed on X, ticket prices on TikTok = one cluster, not three separate items.
 6. **Synthesized into one brief.** Grounded in specific data. Cited by source. Ranked by what people actually engage with. Not "here's what I found." It's "here's what matters."
 7. **Then it becomes your expert.** After one run, your Claude session knows everything the community knows. Ask follow-up questions. Have it write prompts, draft emails, plan trips, architect systems - all grounded in what's real right now.