[codex] Add structured issue-thread interactions (#4244)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies.
> - Operators supervise that work through issues, comments, approvals,
and the board UI.
> - Some agent proposals need structured board/user decisions, not
hidden markdown conventions or heavyweight governed approvals.
> - Issue-thread interactions already provide a natural thread-native
surface for proposed tasks and questions.
> - This pull request extends that surface with request confirmations,
richer interaction cards, and agent/plugin/MCP helpers.
> - The benefit is that plan approvals and yes/no decisions become
explicit, auditable, and resumable without losing the single-issue
workflow.

## What Changed

- Added persisted issue-thread interactions for suggested tasks,
structured questions, and request confirmations.
- Added board UI cards for interaction review, selection, question
answers, and accept/reject confirmation flows.
- Added MCP and plugin SDK helpers for creating interaction cards from
agents/plugins.
- Updated agent wake instructions, onboarding assets, Paperclip skill
docs, and public docs to prefer structured confirmations for
issue-scoped decisions.
- Rebased the branch onto `public-gh/master` and renumbered branch
migrations to `0063` and `0064`; the idempotency migration uses `ADD
COLUMN IF NOT EXISTS` for old branch users.

## Verification

- `git diff --check public-gh/master..HEAD`
- `pnpm exec vitest run packages/adapter-utils/src/server-utils.test.ts
packages/mcp-server/src/tools.test.ts
packages/shared/src/issue-thread-interactions.test.ts
ui/src/lib/issue-thread-interactions.test.ts
ui/src/lib/issue-chat-messages.test.ts
ui/src/components/IssueThreadInteractionCard.test.tsx
ui/src/components/IssueChatThread.test.tsx
server/src/__tests__/issue-thread-interaction-routes.test.ts
server/src/__tests__/issue-thread-interactions-service.test.ts
server/src/services/issue-thread-interactions.test.ts` -> 9 files / 79
tests passed
- `pnpm -r typecheck` -> passed, including `packages/db` migration
numbering check

## Risks

- Medium: this adds a new issue-thread interaction model across
db/shared/server/ui/plugin surfaces.
- Migration risk is reduced by placing this branch after current master
migrations (`0063`, `0064`) and making the idempotency column add
idempotent for users who applied the old branch numbering.
- UI interaction behavior is covered by component tests, but this PR
does not include browser screenshots.

> 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, GPT-5-class coding agent runtime. Exact model ID and
context window are not exposed in this Paperclip run; tool use and local
shell/code execution were enabled.

## 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 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] I will address all Greptile and reviewer comments before
requesting merge

---------

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

docs/api/issues.md

@@ -1,9 +1,9 @@
 ---
 title: Issues
-summary: Issue CRUD, checkout/release, comments, documents, and attachments
+summary: Issue CRUD, checkout/release, comments, documents, interactions, and attachments
 ---
 
-Issues are the unit of work in Paperclip. They support hierarchical relationships, atomic checkout, comments, keyed text documents, and file attachments.
+Issues are the unit of work in Paperclip. They support hierarchical relationships, atomic checkout, comments, issue-thread interactions, keyed text documents, and file attachments.
 
 ## List Issues
 
@@ -121,6 +121,65 @@ POST /api/issues/{issueId}/comments
 
 @-mentions (`@AgentName`) in comments trigger heartbeats for the mentioned agent.
 
+## Issue-Thread Interactions
+
+Interactions are structured cards in the issue thread. Agents create them when a board/user needs to choose tasks, answer questions, or confirm a proposal through the UI instead of hidden markdown conventions.
+
+### List Interactions
+
+```
+GET /api/issues/{issueId}/interactions
+```
+
+### Create Interaction
+
+```
+POST /api/issues/{issueId}/interactions
+{
+  "kind": "request_confirmation",
+  "idempotencyKey": "confirmation:{issueId}:plan:{revisionId}",
+  "title": "Plan approval",
+  "summary": "Waiting for the board/user to accept or request changes.",
+  "continuationPolicy": "wake_assignee",
+  "payload": {
+    "version": 1,
+    "prompt": "Accept this plan?",
+    "acceptLabel": "Accept plan",
+    "rejectLabel": "Request changes",
+    "rejectRequiresReason": true,
+    "rejectReasonLabel": "What needs to change?",
+    "detailsMarkdown": "Review the latest plan document before accepting.",
+    "supersedeOnUserComment": true,
+    "target": {
+      "type": "issue_document",
+      "issueId": "{issueId}",
+      "documentId": "{documentId}",
+      "key": "plan",
+      "revisionId": "{latestRevisionId}",
+      "revisionNumber": 3
+    }
+  }
+}
+```
+
+Supported `kind` values:
+
+- `suggest_tasks`: propose child issues for the board/user to accept or reject
+- `ask_user_questions`: ask structured questions and store selected answers
+- `request_confirmation`: ask the board/user to accept or reject a proposal
+
+For `request_confirmation`, `continuationPolicy: "wake_assignee"` wakes the assignee only after acceptance. Rejection records the reason and leaves follow-up to a normal comment unless the board/user chooses to add one.
+
+### Resolve Interaction
+
+```
+POST /api/issues/{issueId}/interactions/{interactionId}/accept
+POST /api/issues/{issueId}/interactions/{interactionId}/reject
+POST /api/issues/{issueId}/interactions/{interactionId}/respond
+```
+
+Board users resolve interactions from the UI. Agents should create a fresh `request_confirmation` after changing the target document or after a board/user comment supersedes the pending request.
+
 ## Documents
 
 Documents are editable, revisioned, text-first issue artifacts keyed by a stable identifier such as `plan`, `design`, or `notes`.