fix(training): bundle reference content + use docker bridge gateway

The Style Studio's curator-prompt + chat features read reference docs
from disk at runtime. Two issues from the initial production run:

1. Dockerfile + .dockerignore excluded .claude/, docs/, and most of
   skills/. Now COPY the four specific files the new endpoints need:
     - .claude/agents/hermes-curator.md
     - skills/decision/SKILL.md
     - docs/legal-decision-lessons.md
     - docs/corpus-analysis.md
   .dockerignore opens whitelists for just those files.

2. Coolify's custom_docker_run_options=--add-host=host.docker.internal:host-gateway
   is not honored on dockerimage build_pack apps (ExtraHosts stayed []).
   Switch chat_proxy.py default to http://10.0.1.1:8770 — the docker0
   bridge gateway, same pattern Paperclip uses for 3100. Bind the host
   pm2 service to 0.0.0.0:8770 so the container can reach it via the
   bridge IP. Oracle Cloud's security list keeps the port unreachable
   from the public internet.

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

Dockerfile

@@ -61,6 +61,18 @@ COPY mcp-server/src/ ./mcp-server/src/
 # (Path(__file__).resolve().parents[4] / "skills/docx/decision_template.docx")
 COPY skills/docx/decision_template.docx ./skills/docx/decision_template.docx
 
+# Reference content the /training tab reads at runtime:
+#   - .claude/agents/hermes-curator.md → GET /api/training/curator/prompt
+#   - skills/decision/SKILL.md         → system prompt for the chat
+#   - docs/legal-decision-lessons.md   → system prompt for the chat
+#   - docs/corpus-analysis.md          → system prompt for the chat
+#
+# These are read-only at runtime; chair edits go through git, not the container.
+COPY .claude/agents/hermes-curator.md ./.claude/agents/hermes-curator.md
+COPY skills/decision/SKILL.md ./skills/decision/SKILL.md
+COPY docs/legal-decision-lessons.md ./docs/legal-decision-lessons.md
+COPY docs/corpus-analysis.md ./docs/corpus-analysis.md
+
 # Make mcp-server source available to web/app.py (it does sys.path.insert for legal_mcp)
 ENV PYTHONPATH=/app/mcp-server/src