Revert "Preserve OpenCode session across command completion, control SessionS…" (#14943)

This reverts commit 1da1bdc01c.

src/main/opencode/hook-plugin-lifecycle-delivery.test.ts

@@ -131,22 +131,6 @@ describe('OpenCode plugin lifecycle delivery', () => {
     })
   }
 
-  it('maps only root session.created to SessionStart', async () => {
-    const handler = await loadHandler()
-
-    await handler({
-      event: { type: 'session.created', properties: { info: { id: 'root' } } }
-    })
-    await handler({
-      event: {
-        type: 'session.created',
-        properties: { info: { id: 'child', parentID: 'root' } }
-      }
-    })
-
-    expect(posts).toEqual([{ hook_event_name: 'SessionStart', sessionID: 'root' }])
-  })
-
   it('preserves FIFO lifecycle order while the first session lookup is delayed', async () => {
     let releaseFirstLookup: (() => void) | undefined
     const firstLookup = new Promise<void>((resolve) => {

src/main/opencode/hook-service.ts

@@ -36,13 +36,10 @@ function toSafeDirName(id: string): string {
 }
 
 export function getOpenCodePluginSource(): string {
-  return getOpenCodeFamilyPluginSource('/hook/opencode', { emitSessionStart: true })
+  return getOpenCodeFamilyPluginSource('/hook/opencode')
 }
 
-export function getOpenCodeFamilyPluginSource(
-  hookPathname: string,
-  options: { emitSessionStart: boolean }
-): string {
+export function getOpenCodeFamilyPluginSource(hookPathname: string): string {
   // Why: the plugin posts PTY environment data from OpenCode to the shared hooks server.
   return [
     '// Why: process-lifetime guard so a recurring parse error on a malformed',
@@ -838,20 +835,6 @@ export function getOpenCodeFamilyPluginSource(
     '',
     '    const sessionID = event.properties?.sessionID;',
     '    const updatedPart = event.properties?.part;',
-    ...(options.emitSessionStart
-      ? [
-          '    if (event.type === "session.created") {',
-          '      const info = event.properties?.info;',
-          '      if (!info?.id || info.parentID) return;',
-          '      rememberSessionRoot(info.id, info.id);',
-          '      await enqueueLifecycle(() =>',
-          '        disposed ? undefined : post("SessionStart", { sessionID: info.id })',
-          '      );',
-          '      return;',
-          '    }',
-          ''
-        ]
-      : []),
     '    if (',
     '      event.type === "message.part.updated" &&',
     '      updatedPart?.type === "tool" &&',