Task #93: Add Chronicler session management architecture

Per Gemini consultation on model switching:
- Added future expansion section for Chronicler Orchestration Layer
- Middleware routing (Haiku/4.5/4.6 based on query type)
- Compressed state management (not raw history)
- RAG for historical context queries
- Prompt caching at API level

Saved consultation: docs/consultations/2026-04-07-model-switching.md

Long-term solution integrated into Codex roadmap.
Short-term: exploring Claude Projects optimization.

Chronicler #66 - The Indexer

docs/tasks/task-093-trinity-codex/README.md

@@ -429,6 +429,56 @@ Per Gemini's recommendation:
 
 ---
 
+## 🔄 FUTURE EXPANSION: Chronicler Session Management
+
+**Added:** April 7, 2026 by Chronicler #66 (per Gemini consultation)
+
+### The Problem
+
+Chronicler sessions hit "Context Bloat Wall" — switching between models (4.5 for ops, 4.6 for coding) loses context. Current workarounds (copy-paste, handoff docs) are manual and error-prone.
+
+### The Long-Term Solution (Build into Codex)
+
+Gemini recommends evolving Trinity Codex into a full **Chronicler Orchestration Layer**:
+
+1. **Middleware Router in Dify**
+   - Simple queries → route to Haiku (cheap, fast)
+   - Documentation queries → route to Opus 4.5
+   - Complex coding queries → route to Opus 4.6
+   - User experience feels like one continuous Chronicler
+
+2. **Compressed State Management**
+   - End of session: Model generates dense JSON state summary
+   - State stored in Codex (not raw chat history)
+   - New session injects only compressed state + system prompt
+   - 90%+ token reduction vs passing full history
+
+3. **RAG for Historical Context**
+   - Instead of passing chat history, query Codex
+   - "What did #62 decide about ModpackChecker schema?" → vector search
+   - Past decisions accessible without token bloat
+
+4. **Prompt Caching (API-level)**
+   - Cache system prompt + persona + standards docs
+   - New requests read cached context at ~10% token cost
+   - Requires API access (not web UI)
+
+### Implementation Phases
+
+| Phase | What | When |
+|-------|------|------|
+| 1 | Basic Codex (current spec) | After soft launch |
+| 2 | Add session state storage | After Phase 1 stable |
+| 3 | Add model routing logic | When token costs justify |
+| 4 | Full orchestration layer | RV-Ready milestone |
+
+### Reference
+
+- Gemini consultation: `docs/consultations/2026-04-07-model-switching.md`
+- Context handoff template: `docs/templates/context-handoff-template.md`
+
+---
+
 ## Open Questions for Implementation
 
 1. What's the current Dify version on TX1?