[codex] Polish issue interaction selectors (#7668)

## Thinking Path

> - Paperclip is the open source control plane people use to manage AI
agents for work.
> - Issue-thread interactions are the board/agent handoff surface for
structured decisions and confirmations.
> - Accepted checkbox confirmations can include many selected labels,
and inline selectors must stay usable across desktop and mobile devices.
> - The existing accepted checkbox summary capped labels behind a static
`+N more` chip, so operators could not inspect the hidden selections
from the card.
> - The inline selector also skipped search focus on coarse pointers,
which made mobile selection slower and less predictable.
> - This pull request makes the hidden checkbox selections expandable
and restores search focus when the selector opens.
> - The benefit is a more inspectable, faster interaction UI without
changing the interaction API contract.

## Linked Issues or Issue Description

Internal source work: [PAP-10488](/PAP/issues/PAP-10488), split from
[PAP-10495](/PAP/issues/PAP-10495).

### Subsystem affected

ui/ - React + Vite board UI

### Problem or motivation

Accepted checkbox confirmations hide selected values behind a static
count, and inline selector search does not focus on mobile/coarse
pointer devices. That makes accepted interaction cards less inspectable
and makes mobile selection slower than it needs to be.

### Proposed solution

Make hidden accepted checkbox selections expandable/collapsible directly
in the interaction card, and focus the inline selector search input
whenever the selector opens, including coarse pointer environments.

### Alternatives considered

Leaving the static `+N more` chip avoids UI state, but it keeps selected
values hidden from operators. Only restoring desktop focus keeps the old
mobile/coarse pointer gap, so the focus behavior should be consistent
across pointer types.

### Roadmap alignment

This is a small board UI polish change for the existing issue
interaction surface. It does not add a new core roadmap capability or
change the API contract.

## What Changed

- Converted the accepted checkbox `+N more` chip into an expandable
button with a `Show less` control.
- Restored search input focus whenever `InlineEntitySelector` opens,
including coarse pointer environments.
- Updated focused component tests for the expanded selection summary and
mobile/coarse-pointer focus path.
- Adjusted the interaction card test harness to use the same `flushSync`
act helper style used by nearby focused component tests.

## Verification

- `pnpm exec vitest run
ui/src/components/IssueThreadInteractionCard.test.tsx
ui/src/components/InlineEntitySelector.test.tsx` passed in
`~paperclipai/paperclip/.paperclip/worktrees/PAP-10495-interaction-selector-polish`.

## Risks

- Low risk. The change is limited to UI state and focus behavior in
existing components.
- Restoring focus on coarse pointers may open a virtual keyboard on
mobile, but that is intentional for the faster search workflow requested
by this branch.

> 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 local repository
inspection, shell execution, git, and GitHub CLI tool use. Runtime
context window was not exposed by the 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 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
- [ ] All Paperclip CI gates are green
- [ ] 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/src/components/IssueThreadInteractionCard.test.tsx

@@ -1,7 +1,7 @@
 // @vitest-environment jsdom
 
-import { act } from "react";
 import type { ComponentProps, ReactNode } from "react";
+import { flushSync } from "react-dom";
 import { createRoot, type Root } from "react-dom/client";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { IssueThreadInteractionCard } from "./IssueThreadInteractionCard";
@@ -34,6 +34,10 @@ vi.mock("@/lib/router", () => ({
   ),
 }));
 
+function act(callback: () => void) {
+  flushSync(callback);
+}
+
 function renderCard(
   props: Partial<ComponentProps<typeof IssueThreadInteractionCard>> = {},
 ) {
@@ -460,6 +464,48 @@ describe("IssueThreadInteractionCard", () => {
     expect(host.textContent).toContain("+34 more");
   });
 
+  it("expands the hidden accepted selections when the +N more chip is clicked", () => {
+    const host = renderCard({
+      interaction: acceptedManyRequestCheckboxConfirmationInteraction,
+    });
+
+    const countSelectedChips = () =>
+      Array.from(host.querySelectorAll("*")).filter(
+        (node) => node.children.length === 0 && node.textContent?.trim().startsWith("Selected:"),
+      ).length;
+
+    expect(countSelectedChips()).toBe(8);
+
+    const moreButton = Array.from(host.querySelectorAll("button")).find((button) =>
+      button.textContent?.includes("+34 more"),
+    );
+    expect(moreButton).toBeTruthy();
+    moreButton?.focus();
+    expect(document.activeElement).toBe(moreButton);
+
+    act(() => {
+      moreButton?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+    });
+
+    expect(host.textContent).not.toContain("+34 more");
+    expect(countSelectedChips()).toBe(42);
+    expect(document.activeElement).toBe(moreButton);
+
+    const showLessButton = Array.from(host.querySelectorAll("button")).find((button) =>
+      button.textContent?.includes("Show less"),
+    );
+    expect(showLessButton).toBeTruthy();
+    expect(showLessButton).toBe(moreButton);
+
+    act(() => {
+      showLessButton?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+    });
+
+    expect(countSelectedChips()).toBe(8);
+    expect(host.textContent).toContain("+34 more");
+    expect(document.activeElement).toBe(moreButton);
+  });
+
   it("stays compact and scrollable with around 100 options", () => {
     const host = renderCard({
       interaction: manyOptionsRequestCheckboxConfirmationInteraction,