fix(story-mode): no celebration when the turn is not a clean finish

From review round 8: "Mission complete!" with confetti and cheering
helpers sat over balloons saying the page will not work as opened, a
helper's tests have not run, or a problem is left. The final panel is now
calm (no confetti, a neutral robot) whenever work was still out at the
turn's end, nothing worked, or Claude's last words name an open problem
(`page.openNote`: a key point about something wrong, not done, not
checked or not fixed); the last of these reads "Done, with a catch".

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

test/fixtures/story-corpus/background-helpers-reports.expected.json

@@ -12,6 +12,7 @@
     "helpers": 2,
     "helpersRunning": 0,
     "finishedLater": 2,
+    "openNote": true,
     "panels": [
       {
         "kind": "mission",
@@ -81,6 +82,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -127,6 +129,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -176,6 +179,7 @@
     "helpers": 1,
     "helpersRunning": 0,
     "finishedLater": 2,
+    "openNote": true,
     "panels": [
       {
         "kind": "mission",
@@ -242,6 +246,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -291,6 +296,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -337,6 +343,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -396,6 +403,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -432,6 +440,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/bash-script-background-helper.expected.json

@@ -12,6 +12,7 @@
     "helpers": 1,
     "helpersRunning": 0,
     "finishedLater": 1,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -108,6 +109,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -164,6 +166,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/compact-then-plan-mode.expected.json

@@ -12,6 +12,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -101,6 +102,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -147,6 +149,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/errors-push-append.expected.json

@@ -12,6 +12,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -155,6 +156,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -227,6 +229,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -306,6 +309,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/failing-test-on-purpose.expected.json

@@ -12,6 +12,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -104,6 +105,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/long-turn-prompt-added.expected.json

@@ -12,6 +12,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -160,6 +161,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/python-cli-fix-loop.expected.json

@@ -12,6 +12,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/question-tests-first-push.expected.json

@@ -12,6 +12,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": true,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/teammates-then-interrupt.expected.json

@@ -12,6 +12,7 @@
     "helpers": 2,
     "helpersRunning": 0,
     "finishedLater": 2,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -111,6 +112,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": true,
     "panels": [
       {
         "kind": "mission",
@@ -167,6 +169,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -226,6 +229,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",
@@ -318,6 +322,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": false,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/text-plan-dry-run-helper.expected.json

@@ -12,6 +12,7 @@
     "helpers": 1,
     "helpersRunning": 0,
     "finishedLater": 1,
+    "openNote": true,
     "panels": [
       {
         "kind": "mission",
@@ -121,6 +122,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": true,
     "panels": [
       {
         "kind": "mission",

test/fixtures/story-corpus/web-page-node-test.expected.json

@@ -12,6 +12,7 @@
     "helpers": 0,
     "helpersRunning": 0,
     "finishedLater": 0,
+    "openNote": true,
     "panels": [
       {
         "kind": "mission",