[codex] Split PR #4692 UI/QoL updates (#4701)

## Thinking Path

> - Paperclip orchestrates AI agents through a company-scoped control
plane.
> - The affected surface is the board UI for issue threads, issue lists,
routines, dialogs, navigation, and issue review indicators.
> - Closed PR #4692 bundled backend, schema, docs, workflow, and UI/QoL
work into one oversized change set.
> - Greptile could not keep reviewing that broad PR because it exceeded
the 100-file review limit and mixed unrelated concerns.
> - This pull request extracts the UI/QoL slice into a fresh branch
under the review limit while leaving workflow and lockfile churn out.
> - The benefit is a focused review path for the board UI performance
and workflow improvements without reopening the oversized PR.

## What Changed

- Added long issue-thread virtualization, scroll-container binding,
anchor preservation, latest-comment jump targeting, and related
regression/perf fixtures.
- Improved issue list scalability with scroll-based loading, server
offset parameters, and pagination-focused UI tests.
- Reduced new issue dialog typing churn and split dialog action
subscriptions so broad layout/nav surfaces avoid unnecessary renders.
- Added routine variables help and routine description mention options
for users, agents, and projects.
- Added productivity review badge/link UI and fixed the badge to use
Paperclip's company-prefixed router link.
- Kept the split PR below Greptile's review limit and excluded
`.github/workflows/pr.yml` and `pnpm-lock.yaml`.

## Verification

- `pnpm install --no-frozen-lockfile` in the clean worktree to install
`@tanstack/react-virtual` locally without committing lockfile churn.
- `pnpm --filter @paperclipai/ui exec vitest run --config
vitest.config.ts src/components/IssueChatThread.test.tsx
src/components/IssuesList.test.tsx
src/components/NewIssueDialog.test.tsx src/pages/Routines.test.tsx
src/pages/Issues.test.tsx` passed: 5 files, 83 tests.
- `pnpm --filter @paperclipai/ui typecheck` passed.
- `git diff --check origin/master..HEAD` passed.
- Split-scope checks: 53 changed files; no `.github/workflows/pr.yml`;
no `pnpm-lock.yaml`.
- Screenshots were not captured in this heartbeat; the changes are
primarily virtualization, routing, pagination, and editor behavior
covered by focused regression tests.

## Risks

- Moderate UI risk because issue-thread virtualization changes scroll
behavior on long conversations; regression tests cover anchor jumps,
latest-comment targeting, row metadata, and short-thread fallback.
- Moderate integration risk because the issue-list offset parameter and
productivity review field depend on matching API behavior.
- Dependency risk: the UI package adds `@tanstack/react-virtual` while
repository policy keeps `pnpm-lock.yaml` out of PRs, so CI must resolve
dependency changes through the repo's normal lockfile policy.

> 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 coding agent, tool-enabled local repository and
GitHub workflow. Exact runtime context window was not exposed by the
harness.

## 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>

ui/src/components/ProductivityReviewBadge.tsx

@@ -0,0 +1,77 @@
+import { Eye } from "lucide-react";
+import type { IssueProductivityReview } from "@paperclipai/shared";
+import { Link } from "../lib/router";
+import { cn } from "../lib/utils";
+import { createIssueDetailPath } from "../lib/issueDetailBreadcrumb";
+import { Tooltip, TooltipContent, TooltipTrigger } from "./ui/tooltip";
+
+const TRIGGER_LABELS: Record<string, string> = {
+  no_comment_streak: "No-comment streak",
+  long_active_duration: "Long active duration",
+  high_churn: "High churn",
+};
+
+const REVIEW_STATUS_LABELS: Record<string, string> = {
+  todo: "Open",
+  in_progress: "In progress",
+  in_review: "In review",
+  blocked: "Blocked",
+  backlog: "Open",
+};
+
+export function productivityReviewTriggerLabel(
+  trigger: IssueProductivityReview["trigger"],
+): string {
+  if (!trigger) return "Productivity review";
+  return TRIGGER_LABELS[trigger] ?? "Productivity review";
+}
+
+export function ProductivityReviewBadge({
+  review,
+  className,
+  hideLabel = false,
+}: {
+  review: IssueProductivityReview;
+  className?: string;
+  hideLabel?: boolean;
+}) {
+  const label = productivityReviewTriggerLabel(review.trigger);
+  const reviewIdentifier = review.reviewIdentifier ?? review.reviewIssueId.slice(0, 8);
+  const reviewPath = createIssueDetailPath(review.reviewIdentifier ?? review.reviewIssueId);
+  const statusLabel = REVIEW_STATUS_LABELS[review.status] ?? review.status.replace(/_/g, " ");
+
+  return (
+    <Tooltip>
+      <TooltipTrigger asChild>
+        <Link
+          to={reviewPath}
+          className={cn(
+            "inline-flex items-center gap-1 rounded-full border border-amber-500/40 bg-amber-500/10 px-2 py-0.5 text-[10px] font-medium text-amber-700 dark:text-amber-300 shrink-0 hover:bg-amber-500/20 transition-colors",
+            className,
+          )}
+          aria-label={`Under review · productivity review ${reviewIdentifier} (${label})`}
+        >
+          <Eye className="h-3 w-3" aria-hidden />
+          {hideLabel ? null : <span>Under review</span>}
+        </Link>
+      </TooltipTrigger>
+      <TooltipContent>
+        <div className="space-y-1 text-xs">
+          <div className="font-semibold">Productivity review open</div>
+          <div>
+            <span className="text-muted-foreground">Trigger:</span> {label}
+          </div>
+          {typeof review.noCommentStreak === "number" && review.noCommentStreak > 0 ? (
+            <div>
+              <span className="text-muted-foreground">No-comment streak:</span>{" "}
+              {review.noCommentStreak} runs
+            </div>
+          ) : null}
+          <div>
+            <span className="text-muted-foreground">Review:</span> {reviewIdentifier} ({statusLabel})
+          </div>
+        </div>
+      </TooltipContent>
+    </Tooltip>
+  );
+}