Extract index switch policy

docs/prompt-architecture-improvement-plan.md

@@ -416,6 +416,10 @@ Already isolated:
   by `__init__.py`.
 - generation profile, advanced filter, and ethnicity list utility nodes live in
   `node_profile_filter.py`, with registration maps imported by `__init__.py`.
+- index-switch constants, index-base normalization, missing-input behavior,
+  route-output selection, status text, and lazy-input selection live in
+  `index_switch_policy.py`; `loop_nodes.py` keeps the ComfyUI node wrapper and
+  accumulator/loop runtime logic.
 - profile-save and accumulator server payload handling lives in
   `server_routes.py`; `__init__.py` only wires those pure handlers to ComfyUI
   JSON responses, and `tools/prompt_smoke.py` covers the handlers without

docs/prompt-pool-routing-map.md

@@ -722,7 +722,7 @@ These do not own prompt pool wording, but they affect execution and review:
 | Node family | Files | Purpose |
 | --- | --- | --- |
 | Loop nodes | `loop_nodes.py`, `web/loop_slots.js` | While/for loop execution and carry values. |
-| Index switch | `loop_nodes.py`, `web/index_switch_slots.js` | Multi-input to selected output, and selected input to multi-output routing. |
+| Index switch | `loop_nodes.py`, `index_switch_policy.py`, `web/index_switch_slots.js` | Multi-input to selected output, and selected input to multi-output routing. Pure index-base, missing-input, route-output, status, and lazy-input policy lives in `index_switch_policy.py`. |
 | Accumulator | `loop_nodes.py`, `web/accumulator_preview.js` | Stores generated values/images during workflow execution and previews/reorders/deletes them. |
 | Persistent text preview | `loop_nodes.py`, `web/preview_any_text.js` | Stores any value as text and keeps it after workflow reload. |
 | Builder node wrappers | `node_builder.py`, imported by `__init__.py` | Direct prompt builder and config-driven prompt builder ComfyUI declarations. |