Session.ContextReady stores full LLM context inline on every turn

[rita-aga]

Problem

Session.ContextReady events store the full prepared_context_inline_json (the complete messages array sent to the LLM) in the event payload on every turn. A 200-turn session emits 200 ContextReady events, each ~50-70KB.

Evidence (Katagami pipeline, 5-query run, 112 sessions)

• ContextReady events: 300MB of a 491MB database (61%)
• Same data also exists in SessionEntry events (15MB) and ots_trajectories (5MB) — triple-stored
• 4,432 events use inline JSON; only 6 use prepared_context_file_id reference

Impact

Per-session storage: ~3MB average, dominated by redundant context copies. 14 design languages produced 491MB of data. The per-turn inline context is the primary storage driver.