refactor(agent-loop): simplify observable state machine

docs/persistence-catalog.md

@@ -78,7 +78,7 @@ export type SessionEvent<T extends SessionEventType = SessionEventType> = {
 }[T]
 ```
 
-Sources: [`packages/core/session/src/types.ts:292`](../packages/core/session/src/types.ts) · [`packages/core/session/src/types.ts:305`](../packages/core/session/src/types.ts) · [`packages/core/session/src/types.ts:334`](../packages/core/session/src/types.ts) · [`packages/core/session/src/types.ts:366`](../packages/core/session/src/types.ts)
+Sources: [`packages/core/session/src/types.ts:288`](../packages/core/session/src/types.ts) · [`packages/core/session/src/types.ts:301`](../packages/core/session/src/types.ts) · [`packages/core/session/src/types.ts:330`](../packages/core/session/src/types.ts) · [`packages/core/session/src/types.ts:362`](../packages/core/session/src/types.ts)
 
 ## Events
 
@@ -150,7 +150,7 @@ Source: [`packages/ui/user-approval/src/index.ts:67`](../packages/ui/user-approv
 
 Types: [StreamChunk](core-data-structures/llm-streaming.md)
 
-Source: [`packages/core/session/src/types.ts:238`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:234`](../packages/core/session/src/types.ts)
 
 #### `assistant/message` — surface
 
@@ -166,7 +166,7 @@ Source: [`packages/core/session/src/types.ts:238`](../packages/core/session/src/
 
 Types: [ContentBlock](core-data-structures/core.md) · [TokenUsage](core-data-structures/llm-streaming.md)
 
-Source: [`packages/core/session/src/types.ts:245`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:241`](../packages/core/session/src/types.ts)
 
 ### `compact/*`
 
@@ -329,7 +329,7 @@ Source: [`packages/plan/plan-mode/src/index.ts:41`](../packages/plan/plan-mode/s
 
 Types: [ContentBlock](core-data-structures/core.md) · [MessageSource](core-data-structures/core.md)
 
-Source: [`packages/core/session/src/types.ts:236`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:232`](../packages/core/session/src/types.ts)
 
 ### `request/*`
 
@@ -343,7 +343,7 @@ Source: [`packages/core/session/src/types.ts:236`](../packages/core/session/src/
 'request/header': { header: EpochHeader; reason: RequestHeaderReason }
 ```
 
-Source: [`packages/core/session/src/types.ts:280`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:276`](../packages/core/session/src/types.ts)
 
 ### `sandbox/*`
 
@@ -399,7 +399,7 @@ Source: [`packages/session-title/session-title-llm/src/index.ts:44`](../packages
 'steering/message': UserMessageData & { turn: number }
 ```
 
-Source: [`packages/core/session/src/types.ts:273`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:269`](../packages/core/session/src/types.ts)
 
 ### `step/*`
 
@@ -410,7 +410,7 @@ Source: [`packages/core/session/src/types.ts:273`](../packages/core/session/src/
 'step/end': { turn: number; step: number }
 ```
 
-Source: [`packages/core/session/src/types.ts:222`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:218`](../packages/core/session/src/types.ts)
 
 #### `step/start` — log-only
 
@@ -419,7 +419,7 @@ Source: [`packages/core/session/src/types.ts:222`](../packages/core/session/src/
 'step/start': { turn: number; step: number }
 ```
 
-Source: [`packages/core/session/src/types.ts:220`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:216`](../packages/core/session/src/types.ts)
 
 ### `todo/*`
 
@@ -432,7 +432,7 @@ Source: [`packages/core/session/src/types.ts:220`](../packages/core/session/src/
 
 Types: [TodoItem](core-data-structures/session.md)
 
-Source: [`packages/core/session/src/types.ts:275`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:271`](../packages/core/session/src/types.ts)
 
 ### `tool/*`
 
@@ -449,7 +449,7 @@ Source: [`packages/core/session/src/types.ts:275`](../packages/core/session/src/
 
 Types: [CallId](core-data-structures/core.md)
 
-Source: [`packages/core/session/src/types.ts:251`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:247`](../packages/core/session/src/types.ts)
 
 #### `tool/code-dispatch` — log-only
 
@@ -503,7 +503,7 @@ Source: [`packages/core/tools/src/code-mode.ts:34`](../packages/core/tools/src/c
 
 Types: [CallId](core-data-structures/core.md) · [ContentBlock](core-data-structures/core.md)
 
-Source: [`packages/core/session/src/types.ts:263`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:259`](../packages/core/session/src/types.ts)
 
 ### `turn/*`
 
@@ -521,7 +521,7 @@ Source: [`packages/core/session/src/types.ts:263`](../packages/core/session/src/
 
 Types: [TurnEndReason](core-data-structures/session.md)
 
-Source: [`packages/core/session/src/types.ts:218`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:214`](../packages/core/session/src/types.ts)
 
 #### `turn/start` — log-only
 
@@ -534,7 +534,7 @@ Source: [`packages/core/session/src/types.ts:218`](../packages/core/session/src/
 
 Types: [TurnTrigger](core-data-structures/session.md)
 
-Source: [`packages/core/session/src/types.ts:211`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:207`](../packages/core/session/src/types.ts)
 
 ### `user/*`
 
@@ -552,4 +552,4 @@ Source: [`packages/core/session/src/types.ts:211`](../packages/core/session/src/
 'user/message': UserMessageData
 ```
 
-Source: [`packages/core/session/src/types.ts:231`](../packages/core/session/src/types.ts)
+Source: [`packages/core/session/src/types.ts:227`](../packages/core/session/src/types.ts)