feat(training): Style Studio — upload, rich corpus, lessons, curator portrait, chat

Six-phase upgrade of /training from a read-only dashboard into a full
Style Studio for managing Daphna's style corpus.

- Upload Sheet on /training: file → proofread preview → commit (no more
  CLI-only `upload-training` skill).
- Rich corpus metadata: GET /api/training/corpus returns summary, outcome,
  key_principles, page_count, parties (regex), legal_citation, lessons_count.
  PATCH endpoint for chair edits. CorpusDetailDrawer with 4 tabs (details
  /content/lessons/patterns) replaces the bare table row.
- LLM metadata enrichment: style_metadata_extractor + MCP tools
  (style_corpus_enrich, style_corpus_pending_enrichment) fill summary
  /outcome/key_principles via claude_session (free, host-side).
- Per-decision lessons: new decision_lessons table + 4 REST endpoints +
  LessonsTab in drawer; hermes-curator now auto-posts findings as
  decision_lessons(source=curator).
- Curator Portrait tab: prompt rendered with link to Gitea, recent
  curator findings, style_analyzer training prompts, propose-change
  form that writes proposals to data/curator-proposals/ for manual
  chair review (no auto-mutation of the agent file).
- Style chat tab: SSE-streamed conversations with the style agent.
  New host-side pm2 service (legal-chat-service, port 8770) wraps
  claude CLI with stream-json + --resume continuation; FastAPI proxies
  via host.docker.internal. Zero API cost — uses chaim's claude.ai
  subscription. chat_conversations + chat_messages persist history.

Architecture: keeps the existing rule that claude_session only runs
on the host (not the container). The new legal-chat-service is the
canonical bridge between the container and the local CLI for the chat
feature; everything else (upload, metadata, lessons) stays within the
container's existing capabilities.

Audit script (scripts/audit_training_corpus.py) included for verifying
which corpus rows still need enrichment.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/legal-chat-service.config.cjs

@@ -0,0 +1,48 @@
+/**
+ * pm2 ecosystem entry for legal-chat-service — the host-side SSE bridge
+ * to ``claude`` CLI that powers the /training chat tab.
+ *
+ * Why pm2:
+ *   - Auto-restart if the process dies (claude CLI subprocess failures
+ *     should never leave the service in a half-dead state).
+ *   - Log rotation matches paperclip's behavior so the chair sees
+ *     consistent log paths under ~/.pm2/logs/.
+ *
+ * Install (once):
+ *     pm2 start /home/chaim/legal-ai/scripts/legal-chat-service.config.cjs
+ *     pm2 save
+ *
+ * Smoke test:
+ *     curl http://127.0.0.1:8770/health
+ *     # → {"ok":true,"service":"legal-chat-service"}
+ *
+ * Update:
+ *     pm2 restart legal-chat-service
+ *
+ * Stop:
+ *     pm2 stop legal-chat-service
+ */
+
+module.exports = {
+  apps: [
+    {
+      name: "legal-chat-service",
+      cwd: "/home/chaim/legal-ai/mcp-server",
+      // Run the in-package server via the venv interpreter so all
+      // imports (claude_session, etc) resolve.
+      script: "/home/chaim/legal-ai/mcp-server/.venv/bin/python",
+      args: "-m legal_mcp.chat_service.server --port 8770",
+      // claude CLI looks up credentials under HOME — make sure it
+      // sees Daphna's session, not an empty container HOME.
+      env: {
+        HOME: "/home/chaim",
+        PATH: "/home/chaim/.local/bin:/usr/local/bin:/usr/bin:/bin",
+        PYTHONUNBUFFERED: "1",
+      },
+      restart_delay: 5000,
+      max_restarts: 10,
+      autorestart: true,
+      max_memory_restart: "500M",
+    },
+  ],
+};