Overhaul Feynman harness: streamline agents, prompts, and extensions

Remove legacy chains, skills, and config modules. Add citation agent,
SYSTEM.md, modular research-tools extension, and web-access layer.
Add ralph-wiggum to Pi package stack for long-running loops.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

prompts/compare.md

@@ -4,17 +4,8 @@ description: Compare multiple sources on a topic and produce a source-grounded m
 Compare sources for: $@
 
 Requirements:
-- Use the `researcher` subagent to gather source material when the comparison set is broad, and the `verifier` subagent to pressure-test the resulting matrix when needed.
-- Identify the strongest relevant primary sources first.
-- For current or market-facing topics, use `web_search` and `fetch_content` to gather up-to-date primary sources before comparing them.
-- For academic claims, use `alpha_search` and inspect the strongest papers directly.
-- Inspect the top sources directly before comparing them.
-- Build a comparison matrix covering:
-  - source
-  - key claim
-  - evidence type
-  - caveats
-  - confidence
+- Use the `researcher` subagent to gather source material when the comparison set is broad, and the `citation` subagent to verify sources and add inline citations to the final matrix.
+- Build a comparison matrix covering: source, key claim, evidence type, caveats, confidence.
 - Distinguish agreement, disagreement, and uncertainty clearly.
+- Save exactly one comparison to `outputs/` as markdown.
 - End with a `Sources` section containing direct URLs for every source used.
-- If the user wants a durable artifact, save exactly one comparison to `outputs/` as markdown.