feat: Add conversation_transcript SQL view (salvaged from PR #112)

[scottwofford]

Summary

Add a human-readable SQL view for conversation logs. This was in PR #112 which had merge conflicts and was closed. The branch still has the code.

Background

During dogfooding (Adrian maze game, 2026-01-03), we queried this view to export conversation history to CSV. It worked well for debugging and creating human-readable logs.

Session Context

Conversation transcript: /Users/scottwofford/build/luthien-private-session-logs/2026-01-03_pr112-salvage.csv

Files to salvage from origin/feature/conversation-log-export

• migrations/007_add_conversation_transcript_view.sql - The SQL view (migration 007 is correct number)
• tests/integration_tests/test_conversation_transcript_view.py - Tests
• docs/database-schema.md - Documentation updates

Implementation commands

git checkout main && git pull
git checkout -b feature/conversation-transcript-view
git checkout origin/feature/conversation-log-export -- migrations/007_add_conversation_transcript_view.sql
git checkout origin/feature/conversation-log-export -- tests/integration_tests/test_conversation_transcript_view.py
git checkout origin/feature/conversation-log-export -- docs/database-schema.md
git add . && git commit -m "feat: add conversation_transcript view for human-readable logs"
git push -u origin feature/conversation-transcript-view
gh pr create --title "feat: conversation_transcript SQL view" --body "Closes #124. Salvaged from #112."

Additional context

• PR Feature: Clean conversation log export #112: Feature: Clean conversation log export #112
• The view extracts prompt/response text from conversation_events JSON payloads
• Handles both OpenAI and Anthropic message formats