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>

CLAUDE.md

@@ -91,6 +91,16 @@
 - שינויי קוד נכנסים לתוקף אחרי `pm2 restart paperclip`
 - **אין צורך ב-Docker או Coolify**
 
+**legal-chat-service** — רץ **מקומית דרך pm2** (חדש, מאפריל 2026):
+- פורט: `localhost:8770` (loopback בלבד)
+- שירות aiohttp קצר שעוטף את `claude` CLI ב-streaming + session continuation, ומשרת את הטאב "שיחה" בדף `/training`. הקונטיינר משדל אליו proxy דרך `host.docker.internal:8770`.
+- קוד: [mcp-server/src/legal_mcp/chat_service/](mcp-server/src/legal_mcp/chat_service/)
+- התקנה: `pm2 start /home/chaim/legal-ai/scripts/legal-chat-service.config.cjs && pm2 save`
+- בריאות: `curl http://127.0.0.1:8770/health` → `{"ok":true,...}`
+- שינויי קוד: `pm2 restart legal-chat-service`
+- **אפס עלות API** — claude CLI משתמש ב-claude.ai subscription של chaim. הנחת היסוד של `claude_session.py` (claude CLI מקומי בלבד) נשמרת — השירות הזה הוא הגשר הרשמי בין הקונטיינר לחוץ.
+- Coolify dependency: ה-Service Definition של legal-ai חייב להכיל `extra_hosts: host.docker.internal:host-gateway` (אחרת ה-proxy יקבל ConnectError).
+
 ---
 
 ## מבנה תיקיות