[codex] Add checkbox confirmation issue interactions (#7649)

## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work.
> - Agent work is coordinated through issues, comments, interactions,
and approval-style handoffs.
> - Existing issue-thread interactions could ask questions, suggest
tasks, and request confirmation, but they did not support a structured
checkbox confirmation payload for choosing one or more options.
> - That gap made board/user confirmations harder to validate
consistently across API callers, plugin helpers, CLI tooling, and the
UI.
> - This pull request adds the shared checkbox confirmation contract,
server handling, client helpers, and issue-thread UI needed to render
and submit structured selections.
> - The benefit is that agents can request bounded multi-select
confirmations in the same audited issue-thread flow as other Paperclip
interactions.

## Linked Issues or Issue Description

- No public GitHub issue found for this exact branch. Internal Paperclip
issue: PAP-10415 / PAP-10441 requested creating this PR for the checkbox
confirmation issue-thread UI component work.
- GitHub duplicate search performed for checkbox confirmation /
issue-thread interaction PRs; no matching open PR was found.
- Related issue search result `#7497` was unrelated company file cleanup
work, so it is not linked as a related issue.

## What Changed

- Added shared types, validators, constants, and tests for
`request_checkbox_confirmation` interactions.
- Extended server issue-thread interaction service and routes for
checkbox confirmation creation, validation, expiration, and response
handling.
- Added CLI, MCP, and plugin SDK helper coverage so external callers can
create the new interaction shape consistently.
- Updated the issue-thread interaction UI to render checkbox
confirmations with min/max bounds, selection summaries, stale-target
states, and accept/decline flows.
- Documented the checkbox confirmation interaction contract in the
Paperclip skill/API reference.

## Verification

- Rebased cleanly on `paperclipai/paperclip` `master` fetched into
`public-gh/master` at `a4fa0eaf5`.
- Confirmed the PR diff does not include `pnpm-lock.yaml` or
`.github/workflows` changes.
- Ran focused tests with `NODE_ENV=test`:

```sh
NODE_ENV=test pnpm run preflight:workspace-links
NODE_ENV=test pnpm exec vitest run packages/shared/src/issue-thread-interactions.test.ts server/src/__tests__/issue-thread-interaction-routes.test.ts server/src/__tests__/issue-thread-interactions-service.test.ts ui/src/components/IssueThreadInteractionCard.test.tsx ui/src/lib/issue-thread-interactions.test.ts cli/src/__tests__/issue-subresources.test.ts cli/src/__tests__/project-goal.test.ts packages/mcp-server/src/tools.test.ts packages/plugins/sdk/tests/testing-actions.test.ts
```

Result: 8 test files passed, 78 tests passed.
- CI on latest head `63b9e55` is green.
- Greptile Review passed on latest head; GraphQL review-thread check
shows all Greptile threads resolved.

## Risks

- Medium surface area because the interaction contract touches shared
validators, server routes/services, UI rendering, CLI, MCP, plugin SDK
helpers, and docs.
- No database migrations are included.
- `pnpm-lock.yaml` is intentionally excluded per repository lockfile
policy.
- UI screenshots are not attached because the task explicitly requested
not to add design screenshots or images unless they were part of the
work; component tests cover the new rendering and interaction states.

> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.

## Model Used

- OpenAI Codex coding agent based on GPT-5, with repository file access,
shell command execution, git/GitHub CLI tooling, and Paperclip
control-plane API access. Exact hosted model ID/context-window metadata
is not exposed inside this runtime.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

ui/storybook/stories/issue-thread-interactions.stories.tsx

@@ -4,9 +4,12 @@ import { IssueChatThread } from "@/components/IssueChatThread";
 import { IssueThreadInteractionCard } from "@/components/IssueThreadInteractionCard";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
 import {
+  acceptedManyRequestCheckboxConfirmationInteraction,
+  acceptedRequestCheckboxConfirmationInteraction,
   acceptedSuggestedTasksInteraction,
   answeredAskUserQuestionsInteraction,
   acceptedRequestConfirmationInteraction,
+  boundedRequestCheckboxConfirmationInteraction,
   commentExpiredRequestConfirmationInteraction,
   failedRequestConfirmationInteraction,
   genericPendingRequestConfirmationInteraction,
@@ -15,20 +18,25 @@ import {
   issueThreadInteractionFixtureMeta,
   issueThreadInteractionLiveRuns,
   issueThreadInteractionTranscriptsByRunId,
+  manyOptionsRequestCheckboxConfirmationInteraction,
   mixedIssueThreadInteractions,
   optionalDeclineRequestConfirmationInteraction,
   pendingAskUserQuestionsInteraction,
+  pendingRequestCheckboxConfirmationInteraction,
   pendingRequestConfirmationInteraction,
   pendingSuggestedTasksInteraction,
   planApprovalAcceptedRequestConfirmationInteraction,
   rejectedNoReasonRequestConfirmationInteraction,
+  rejectedRequestCheckboxConfirmationInteraction,
   rejectedRequestConfirmationInteraction,
   rejectedSuggestedTasksInteraction,
+  staleTargetRequestCheckboxConfirmationInteraction,
   staleTargetRequestConfirmationInteraction,
 } from "@/fixtures/issueThreadInteractionFixtures";
 import type {
   AskUserQuestionsAnswer,
   AskUserQuestionsInteraction,
+  RequestCheckboxConfirmationInteraction,
   RequestConfirmationInteraction,
   SuggestTasksInteraction,
 } from "@/lib/issue-thread-interactions";
@@ -191,6 +199,47 @@ function InteractiveRequestConfirmationCard() {
   );
 }
 
+function InteractiveRequestCheckboxConfirmationCard({
+  pending,
+  accepted,
+  rejected,
+}: {
+  pending: RequestCheckboxConfirmationInteraction;
+  accepted: RequestCheckboxConfirmationInteraction;
+  rejected: RequestCheckboxConfirmationInteraction;
+}) {
+  const [interaction, setInteraction] = useState<RequestCheckboxConfirmationInteraction>(pending);
+
+  return (
+    <IssueThreadInteractionCard
+      interaction={interaction}
+      agentMap={storybookAgentMap}
+      currentUserId={issueThreadInteractionFixtureMeta.currentUserId}
+      userLabelMap={boardUserLabels}
+      onAcceptInteraction={(_interaction, _selectedClientKeys, selectedOptionIds) =>
+        setInteraction({
+          ...accepted,
+          payload: pending.payload,
+          result: {
+            version: 1,
+            outcome: "accepted",
+            selectedOptionIds: selectedOptionIds ?? [],
+          },
+        })}
+      onRejectInteraction={(_interaction, reason) =>
+        setInteraction({
+          ...rejected,
+          payload: pending.payload,
+          result: {
+            version: 1,
+            outcome: "rejected",
+            reason: reason || rejected.result?.reason || null,
+          },
+        })}
+    />
+  );
+}
+
 function AutoOpenDeclineRequestConfirmationCard({
   interaction,
 }: {
@@ -224,7 +273,7 @@ const meta = {
     docs: {
       description: {
         component:
-          "Interaction cards for `suggest_tasks`, `ask_user_questions`, and `request_confirmation`, shown both in isolation and inside the real `IssueChatThread` feed.",
+          "Interaction cards for `suggest_tasks`, `ask_user_questions`, `request_confirmation`, and `request_checkbox_confirmation`, shown both in isolation and inside the real `IssueChatThread` feed.",
       },
     },
   },
@@ -524,6 +573,129 @@ export const RequestConfirmationFailed: Story = {
 export const RequestConfirmationAccepted = RequestConfirmationConfirmed;
 export const RequestConfirmationRejected = RequestConfirmationDeclinedWithReason;
 
+export const CheckboxConfirmationPending: Story = {
+  render: () => (
+    <StoryFrame>
+      <ScenarioCard
+        title="Pending checkbox confirmation"
+        description="Board users select any number of options, with frontend-owned select-all and clear controls."
+      >
+        <InteractiveRequestCheckboxConfirmationCard
+          pending={pendingRequestCheckboxConfirmationInteraction}
+          accepted={acceptedRequestCheckboxConfirmationInteraction}
+          rejected={rejectedRequestCheckboxConfirmationInteraction}
+        />
+      </ScenarioCard>
+    </StoryFrame>
+  ),
+};
+
+export const CheckboxConfirmationBounded: Story = {
+  render: () => (
+    <StoryFrame>
+      <ScenarioCard
+        title="Min/max constrained selection"
+        description="The card enforces minimum and maximum selection counts and requires a decline reason."
+      >
+        <InteractiveRequestCheckboxConfirmationCard
+          pending={boundedRequestCheckboxConfirmationInteraction}
+          accepted={acceptedRequestCheckboxConfirmationInteraction}
+          rejected={rejectedRequestCheckboxConfirmationInteraction}
+        />
+      </ScenarioCard>
+    </StoryFrame>
+  ),
+};
+
+export const CheckboxConfirmationAccepted: Story = {
+  render: () => (
+    <StoryFrame>
+      <ScenarioCard
+        title="Accepted checkbox confirmation"
+        description="The resolved state leads with a count and lists the selected labels."
+      >
+        <IssueThreadInteractionCard
+          interaction={acceptedRequestCheckboxConfirmationInteraction}
+          agentMap={storybookAgentMap}
+          currentUserId={issueThreadInteractionFixtureMeta.currentUserId}
+          userLabelMap={boardUserLabels}
+        />
+      </ScenarioCard>
+    </StoryFrame>
+  ),
+};
+
+export const CheckboxConfirmationAcceptedMany: Story = {
+  render: () => (
+    <StoryFrame>
+      <ScenarioCard
+        title="Accepted large selection"
+        description="Large resolved selections summarize by count first and bound the inline chips."
+      >
+        <IssueThreadInteractionCard
+          interaction={acceptedManyRequestCheckboxConfirmationInteraction}
+          agentMap={storybookAgentMap}
+          currentUserId={issueThreadInteractionFixtureMeta.currentUserId}
+          userLabelMap={boardUserLabels}
+        />
+      </ScenarioCard>
+    </StoryFrame>
+  ),
+};
+
+export const CheckboxConfirmationRejected: Story = {
+  render: () => (
+    <StoryFrame>
+      <ScenarioCard
+        title="Declined checkbox confirmation"
+        description="The decline reason stays attached to the request in the thread."
+      >
+        <IssueThreadInteractionCard
+          interaction={rejectedRequestCheckboxConfirmationInteraction}
+          agentMap={storybookAgentMap}
+          currentUserId={issueThreadInteractionFixtureMeta.currentUserId}
+          userLabelMap={boardUserLabels}
+        />
+      </ScenarioCard>
+    </StoryFrame>
+  ),
+};
+
+export const CheckboxConfirmationStaleTarget: Story = {
+  render: () => (
+    <StoryFrame>
+      <ScenarioCard
+        title="Expired by target change"
+        description="The watched plan revision moved before the selection was confirmed."
+      >
+        <IssueThreadInteractionCard
+          interaction={staleTargetRequestCheckboxConfirmationInteraction}
+          agentMap={storybookAgentMap}
+          currentUserId={issueThreadInteractionFixtureMeta.currentUserId}
+          userLabelMap={boardUserLabels}
+        />
+      </ScenarioCard>
+    </StoryFrame>
+  ),
+};
+
+export const CheckboxConfirmationManyOptions: Story = {
+  render: () => (
+    <StoryFrame>
+      <ScenarioCard
+        title="Around 100 options"
+        description="The list stays compact inside a bounded scroll region even with 100 options."
+      >
+        <InteractiveRequestCheckboxConfirmationCard
+          pending={manyOptionsRequestCheckboxConfirmationInteraction}
+          accepted={acceptedManyRequestCheckboxConfirmationInteraction}
+          rejected={rejectedRequestCheckboxConfirmationInteraction}
+        />
+      </ScenarioCard>
+    </StoryFrame>
+  ),
+};
+
 export const ReviewSurface: Story = {
   render: () => (
     <StoryFrame>