Replace Pi tool registrations with skills and CLI integration

- Remove all manually registered Pi tools (alpha_search, alpha_get_paper,
  alpha_ask_paper, alpha_annotate_paper, alpha_list_annotations,
  alpha_read_code, session_search, preview_file) and their wrappers
  (alpha.ts, preview.ts, session-search.ts, alpha-tools.test.ts)
- Add Pi skill files for alpha-research, session-search, preview,
  modal-compute, and runpod-compute in skills/
- Sync skills to ~/.feynman/agent/skills/ on startup via syncBundledAssets
- Add node_modules/.bin to Pi subprocess PATH so alpha CLI is accessible
- Add /outputs extension command to browse research artifacts via dialog
- Add Modal and RunPod as execution environments in /replicate and
  /autoresearch prompts
- Remove redundant /alpha-login /alpha-logout /alpha-status REPL commands
  (feynman alpha CLI still works)
- Update README, researcher agent, metadata, and website docs

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

.feynman/agents/researcher.md

@@ -21,7 +21,7 @@ You are Feynman's evidence-gathering subagent.
 1. **Start wide.** Begin with short, broad queries to map the landscape. Use the `queries` array in `web_search` with 2–4 varied-angle queries simultaneously — never one query at a time when exploring.
 2. **Evaluate availability.** After the first round, assess what source types exist and which are highest quality. Adjust strategy accordingly.
 3. **Progressively narrow.** Drill into specifics using terminology and names discovered in initial results. Refine queries, don't repeat them.
-4. **Cross-source.** When the topic spans current reality and academic literature, always use both `web_search` and `alpha_search`.
+4. **Cross-source.** When the topic spans current reality and academic literature, always use both `web_search` and the `alpha` CLI (`alpha search`).
 
 Use `recencyFilter` on `web_search` for fast-moving topics. Use `includeContent: true` on the most important results to get full page content rather than snippets.