Update index.rst with new system documentation

docs/index.rst

@@ -28,6 +28,14 @@ mostly standalone subsystems.
 - ``docs/how/persistence.txt`` — SQLite storage, what's persisted vs runtime
 - ``docs/how/prompt-system.txt`` — modal prompts, color markup, per-player customization
 - ``docs/how/protocols.rst`` — GMCP/MSDP negotiation, client detection, guard pattern
+- ``docs/how/things-and-verbs.rst`` — verb registry, @verb decorator, TOML verb handlers, dispatch fallback
+- ``docs/how/content-loading.rst`` — TOML content pipeline, startup sequence, global registries
+- ``docs/how/targeting.rst`` — ordinal parsing, priority matching, z-axis filtering
+- ``docs/how/npc-mobs.rst`` — mob templates, behavior states, AI, schedules, dialogue, spawning
+- ``docs/how/time-and-weather.rst`` — game time, seasons, weather simulation, visibility
+- ``docs/how/effects.rst`` — temporary visual overlays on the map (cloud trails, etc)
+- ``docs/how/loot-and-corpses.rst`` — loot tables, corpse creation, decomposition
+- ``docs/how/crafting.rst`` — recipe definitions, ingredient matching, item spawning
 
 combat
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