[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.tsx

@@ -1335,6 +1335,7 @@ function RequestCheckboxConfirmationResolution({
   interaction: RequestCheckboxConfirmationInteraction;
 }) {
   const target = interaction.payload.target ?? null;
+  const [expanded, setExpanded] = useState(false);
 
   if (interaction.status === "accepted") {
     const totalOptions = interaction.payload.options.length;
@@ -1343,8 +1344,13 @@ function RequestCheckboxConfirmationResolution({
       result: interaction.result,
     });
     const selectedCount = interaction.result?.selectedOptionIds?.length ?? selectedLabels.length;
-    const visibleLabels = selectedLabels.slice(0, CHECKBOX_SUMMARY_LABEL_LIMIT);
-    const hiddenCount = selectedLabels.length - visibleLabels.length;
+    const visibleLabels = expanded
+      ? selectedLabels
+      : selectedLabels.slice(0, CHECKBOX_SUMMARY_LABEL_LIMIT);
+    const hiddenCount = selectedLabels.length - CHECKBOX_SUMMARY_LABEL_LIMIT;
+    const hasHiddenLabels = hiddenCount > 0;
+    const chipClassName =
+      "inline-flex items-center rounded-sm border border-border/60 bg-transparent px-2 py-0.5 text-[10px] font-medium uppercase tracking-[0.16em] text-muted-foreground";
 
     return (
       <div className="space-y-3">
@@ -1361,10 +1367,18 @@ function RequestCheckboxConfirmationResolution({
             {visibleLabels.map((label, index) => (
               <TaskField key={`${label}-${index}`} label="Selected" value={label} />
             ))}
-            {hiddenCount > 0 ? (
-              <span className="inline-flex items-center rounded-sm border border-border/60 bg-transparent px-2 py-0.5 text-[10px] font-medium uppercase tracking-[0.16em] text-muted-foreground">
-                +{hiddenCount} more
-              </span>
+            {hasHiddenLabels ? (
+              <button
+                type="button"
+                onClick={() => setExpanded((current) => !current)}
+                className={cn(
+                  chipClassName,
+                  "cursor-pointer transition-colors hover:border-border hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-1",
+                )}
+                aria-expanded={expanded}
+              >
+                {expanded ? "Show less" : `+${hiddenCount} more`}
+              </button>
             ) : null}
           </div>
         ) : null}