fix(program-status): announce a finished OpenCode turn reported only over OSC 7501 (#38222)

OpenCode ends every turn with idle and never reports done, so its idle after
work became a session boundary and no finished notification fired.

src/shared/program-status/agent-status-projector.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, it } from 'vitest'
+import { createProgramStatusProjector } from './agent-status-projector'
+
+const osc = (body: string): string => `\x1b]7501;${body}\x1b\\`
+
+function lastRootStates(data: string[]) {
+  const projector = createProgramStatusProjector(() => 1000)
+  return data.map((chunk) => {
+    const payloads = projector.process(chunk).payloads
+    const last = payloads.at(-1)?.payload
+    return last && { state: last.state, sessionBoundary: last.sessionBoundary }
+  })
+}
+
+describe('createProgramStatusProjector', () => {
+  it('ends an OpenCode turn on idle but not its startup', () => {
+    // Captured from OpenCode 2.2.5, which never reports done.
+    const session = 'ses_e57cc6093ffeU9dbfhOFmwKNgt'
+    expect(
+      lastRootStates([
+        osc('state=idle:app=opencode'),
+        osc('state=working:app=opencode') + osc(`state=working:id=${session}:app=opencode`),
+        osc(`state=clear:id=${session}`) + osc('state=idle:app=opencode')
+      ])
+    ).toEqual([
+      { state: 'done', sessionBoundary: true },
+      { state: 'working', sessionBoundary: undefined },
+      { state: 'done', sessionBoundary: undefined }
+    ])
+  })
+})

src/shared/program-status/agent-status-projector.ts

@@ -154,10 +154,17 @@ export function createProgramStatusProjector(now: () => number = Date.now): Prog
       case 'error':
         return { state: 'done', outcome: 'failure' }
       case 'idle':
-        // Idle may follow startup work (Codex), so it proves rest, not cancellation; interrupt keystrokes own that verdict.
+        if (newInvocation || lastRoot === null || lastRoot.sessionBoundary === true) {
+          return { state: 'done', sessionBoundary: true }
+        }
         // Keep unseen done results when the same invocation rests.
-        return !newInvocation && lastRoot?.state === 'done' && lastRoot.sessionBoundary !== true
-          ? lastRoot
+        if (lastRoot.state === 'done') {
+          return lastRoot
+        }
+        // OpenCode ends every turn with idle, never done, so its idle after work is a turn end with no verdict.
+        // Others' idle may follow startup work (Codex), so it proves rest; interrupt keystrokes own cancellation.
+        return root.app === 'opencode'
+          ? { state: 'done' }
           : { state: 'done', sessionBoundary: true }
     }
   }