Move exec to HookAPI, sessionManager/modelRegistry to HookEventContext

Breaking changes:
- HookEventContext now has sessionManager and modelRegistry (moved from SessionEventBase)
- HookAPI now has exec() method (moved from HookEventContext/HookCommandContext)
- HookRunner constructor takes sessionManager and modelRegistry as required params
- Session events no longer include sessionManager/modelRegistry fields

Hook code migration:
- event.sessionManager -> ctx.sessionManager
- event.modelRegistry -> ctx.modelRegistry
- ctx.exec() -> pi.exec()

Updated:
- src/core/hooks/types.ts - type changes
- src/core/hooks/runner.ts - constructor, createContext
- src/core/hooks/loader.ts - add exec to HookAPI
- src/core/sdk.ts - pass sessionManager/modelRegistry to HookRunner
- src/core/agent-session.ts - remove sessionManager/modelRegistry from events
- src/modes/* - remove setSessionFile calls, update events
- examples/hooks/* - update to new API

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -369,7 +369,6 @@ export class InteractiveMode {
 
 		// Set UI context on hook runner
 		hookRunner.setUIContext(uiContext, true);
-		hookRunner.setSessionFile(this.session.sessionFile);
 
 		// Subscribe to hook errors
 		hookRunner.onError((error) => {
@@ -407,8 +406,6 @@ export class InteractiveMode {
 		// Emit session event
 		await hookRunner.emit({
 			type: "session",
-			sessionManager: this.session.sessionManager,
-			modelRegistry: this.session.modelRegistry,
 			reason: "start",
 		});
 	}
@@ -1204,8 +1201,6 @@ export class InteractiveMode {
 		if (hookRunner?.hasHandlers("session")) {
 			await hookRunner.emit({
 				type: "session",
-				sessionManager: this.session.sessionManager,
-				modelRegistry: this.session.modelRegistry,
 				reason: "shutdown",
 			});
 		}