[codex] Improve issue thread review flow (#4381)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies
> - Issue detail is where operators coordinate review, approvals, and
follow-up work with active runs
> - That thread UI needs to surface blockers, descendants, review
handoffs, and reply ergonomics clearly enough for humans to guide agent
work
> - Several small gaps in the issue-thread flow were making review and
navigation clunkier than necessary
> - This pull request improves the reply composer, descendant/blocker
presentation, interaction folding, and review-request handoff plumbing
together as one cohesive issue-thread workflow slice
> - The benefit is a cleaner operator review loop without changing the
broader task model

## What Changed

- restored and refined the floating reply composer behavior in the issue
thread
- folded expired confirmation interactions and improved post-submit
thread scrolling behavior
- surfaced descendant issue context and inline blocker/paused-assignee
notices on the issue detail view
- tightened large-board first paint behavior in `IssuesList`
- added loose review-request handoffs through the issue
execution-policy/update path and covered them with tests

## Verification

- `pnpm vitest run ui/src/pages/IssueDetail.test.tsx`
- `pnpm vitest run server/src/__tests__/issues-service.test.ts
server/src/__tests__/issue-execution-policy.test.ts`
- `pnpm exec vitest run --project @paperclipai/ui
ui/src/components/IssueChatThread.test.tsx
ui/src/components/IssueProperties.test.tsx
ui/src/components/IssuesList.test.tsx ui/src/lib/issue-tree.test.ts
ui/src/api/issues.test.ts`
- `pnpm exec vitest run --project @paperclipai/adapter-utils
packages/adapter-utils/src/server-utils.test.ts`
- `pnpm exec vitest run --project @paperclipai/server
server/src/__tests__/issue-comment-reopen-routes.test.ts -t "coerces
executor handoff patches into workflow-controlled review wakes|wakes the
return assignee with execution_changes_requested"`
- `pnpm exec vitest run --project @paperclipai/server
server/src/__tests__/issue-execution-policy.test.ts
server/src/__tests__/issues-service.test.ts`

## Visual Evidence

- UI layout changes are covered by the focused issue-thread component
and issue-detail tests listed above. Browser screenshots were not
attachable from this automated greploop environment, so reviewers should
use the running preview for final visual confirmation.

## Risks

- Moderate UI-flow risk: these changes touch the issue detail experience
in multiple spots, so regressions would most likely show up as
thread-layout quirks or incorrect review-handoff behavior

> 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-based coding agent with tool use and code execution
in the Codex CLI environment

## 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
- [x] If this change affects the UI, I have included before/after
screenshots or documented the visual verification path
- [ ] 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>

packages/shared/src/index.ts

@@ -631,6 +631,7 @@ export {
   updateIssueSchema,
   issueExecutionPolicySchema,
   issueExecutionStateSchema,
+  issueReviewRequestSchema,
   issueExecutionWorkspaceSettingsSchema,
   checkoutIssueSchema,
   addIssueCommentSchema,

packages/shared/src/types/index.ts

@@ -119,6 +119,7 @@ export type {
   IssueExecutionStage,
   IssueExecutionStageParticipant,
   IssueExecutionStagePrincipal,
+  IssueReviewRequest,
   IssueExecutionDecision,
   IssueComment,
   IssueThreadInteractionActorFields,

packages/shared/src/types/issue.ts

@@ -168,6 +168,10 @@ export interface IssueExecutionPolicy {
   stages: IssueExecutionStage[];
 }
 
+export interface IssueReviewRequest {
+  instructions: string;
+}
+
 export interface IssueExecutionState {
   status: IssueExecutionStateStatus;
   currentStageId: string | null;
@@ -175,6 +179,7 @@ export interface IssueExecutionState {
   currentStageType: IssueExecutionStageType | null;
   currentParticipant: IssueExecutionStagePrincipal | null;
   returnAssignee: IssueExecutionStagePrincipal | null;
+  reviewRequest: IssueReviewRequest | null;
   completedStageIds: string[];
   lastDecisionId: string | null;
   lastDecisionOutcome: IssueExecutionDecisionOutcome | null;

packages/shared/src/validators/index.ts

@@ -151,6 +151,7 @@ export {
   updateIssueSchema,
   issueExecutionPolicySchema,
   issueExecutionStateSchema,
+  issueReviewRequestSchema,
   issueExecutionWorkspaceSettingsSchema,
   checkoutIssueSchema,
   addIssueCommentSchema,

packages/shared/src/validators/issue.ts

@@ -105,6 +105,10 @@ export const issueExecutionPolicySchema = z.object({
   stages: z.array(issueExecutionStageSchema).default([]),
 });
 
+export const issueReviewRequestSchema = z.object({
+  instructions: z.string().trim().min(1).max(20000),
+}).strict();
+
 export const issueExecutionStateSchema = z.object({
   status: z.enum(ISSUE_EXECUTION_STATE_STATUSES),
   currentStageId: z.string().uuid().nullable(),
@@ -112,6 +116,7 @@ export const issueExecutionStateSchema = z.object({
   currentStageType: z.enum(ISSUE_EXECUTION_STAGE_TYPES).nullable(),
   currentParticipant: issueExecutionStagePrincipalSchema.nullable(),
   returnAssignee: issueExecutionStagePrincipalSchema.nullable(),
+  reviewRequest: issueReviewRequestSchema.nullable().optional().default(null),
   completedStageIds: z.array(z.string().uuid()).default([]),
   lastDecisionId: z.string().uuid().nullable(),
   lastDecisionOutcome: z.enum(ISSUE_EXECUTION_DECISION_OUTCOMES).nullable(),
@@ -164,6 +169,7 @@ export type CreateIssueLabel = z.infer<typeof createIssueLabelSchema>;
 export const updateIssueSchema = createIssueSchema.partial().extend({
   assigneeAgentId: z.string().trim().min(1).optional().nullable(),
   comment: z.string().min(1).optional(),
+  reviewRequest: issueReviewRequestSchema.optional().nullable(),
   reopen: z.boolean().optional(),
   interrupt: z.boolean().optional(),
   hiddenAt: z.string().datetime().nullable().optional(),