feat: make default fun level actually surface comedy (#272)

Most users never touch FUN_LEVEL. Default medium was shipping a stats
block but rarely a Best Takes block, and when it did it was below the
cluster fold where a synthesizing model had already stopped reading.
A 2,304-upvote Reddit comment ("WHAT?! I reached my monthly limit
just reading this post") on the 2026-04-17 Opus 4.7 run sat inside
cluster 11 and never made it into synthesis. Four coordinated changes:

1. render: promote Best Takes above the cluster list so the synthesizer
   sees comedy before it anchors on cluster 1.
2. render: lower medium threshold from 70 to 55 (heuristic maxes at 80),
   drop the two-gem floor to one-gem. Default now reliably emits the
   block on typical runs.
3. rerank: score individual top_comments by upvote ratio to their parent
   thread. A 2,304-upvote comment on a 300-upvote thread now outranks a
   400-upvote comment on a 3,400-upvote thread, which is the viral-wit
   signal. Handles both the LLM scoring path and the heuristic fallback.
4. render: merge scored comment gems into Best Takes alongside candidate
   gems, sorted together. Comment lines show body + parent title +
   r/subreddit or @handle + absolute upvotes.
5. SKILL: tell the synthesizer to quote at least two Best Takes entries
   verbatim, with an example of the new comment format.

Plan: docs/plans/2026-04-17-001-feat-default-fun-surfacing-plan.md

🤖 Generated with Claude Opus 4.7 (1M context) via [Claude Code](https://claude.com/claude-code) + Compound Engineering v2.56.1

Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

SKILL.md

@@ -950,7 +950,7 @@ Read the research output carefully. Pay attention to:
 
 **ANTI-PATTERN TO AVOID**: If user asks about "clawdbot skills" and research returns ClawdBot content (self-hosted AI agent), do NOT synthesize this as "Claude Code skills" just because both involve "skills". Read what the research actually says.
 
-**FUN CONTENT: If the research output includes a "## Best Takes" section or items tagged with `fun:` scores, weave at least 2-3 of the funniest/cleverest quotes into your synthesis.** Reddit comments and X posts with high fun scores are the voice of the people. A 1,338-upvote comment that says "Where's the limewire link" tells you more about the cultural moment than a news article. Quote the actual text. Don't put fun content in a separate section - mix it into the narrative where it fits naturally. This is what makes the report feel alive rather than like a news summary.
+**FUN CONTENT: If the research output includes a "## Best Takes" section at the top of the compact output, quote at least TWO of those items verbatim in your synthesis.** These are pre-ranked comedy and wit lines, pulled from both candidate titles and individual top_comments across every source. A comment entry looks like `"WHAT?! I reached my monthly limit just reading this post" -- r/Anthropic in "Claude Opus 4.7 is a regression" (2,304 upvotes) (fun:88)`. Use the full body, attribute to the container (r/subreddit, @handle on platform), and keep the upvote number so readers can gauge community agreement. Reddit comments and X posts with high fun scores are the voice of the people. Don't put fun content in a separate section - mix it into the narrative where it fits naturally. If no Best Takes section appears, scan items tagged with `fun:` scores in the cluster listings and weave 2-3 of those instead.
 
 **ELI5 MODE: If ELI5_MODE is true for this run, apply these writing guidelines to your ENTIRE synthesis. If ELI5_MODE is false, skip this block completely and write normally.**