[codex] Refine markdown issue reference rendering (#4382)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies
> - Task references are a core part of how operators understand issue
relationships across the UI
> - Those references appear both in markdown bodies and in sidebar
relationship panels
> - The rendering had drifted between surfaces, and inline markdown
pills were reading awkwardly inside prose and lists
> - This pull request unifies the underlying issue-reference treatment,
routes issue descriptions through `MarkdownBody`, and switches inline
markdown references to a cleaner text-link presentation
> - The benefit is more consistent issue-reference UX with better
readability in markdown-heavy views

## What Changed

- unified sidebar and markdown issue-reference rendering around the
shared issue-reference components
- routed resting issue descriptions through `MarkdownBody` so
description previews inherit the richer issue-reference treatment
- replaced inline markdown pill chrome with a cleaner inline reference
presentation for prose contexts
- added and updated UI tests for `MarkdownBody` and `InlineEditor`

## Verification

- `pnpm exec vitest run --project @paperclipai/ui
ui/src/components/MarkdownBody.test.tsx
ui/src/components/InlineEditor.test.tsx`

## Risks

- Moderate UI risk: issue-reference rendering now differs intentionally
between inline markdown and relationship sidebars, so regressions would
show up as styling or hover-preview mismatches

> 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
- [ ] If this change affects the UI, I have included before/after
screenshots
- [ ] 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/IssueProperties.tsx

@@ -1,7 +1,7 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { pickTextColorForPillBg } from "@/lib/color-contrast";
 import { Link } from "@/lib/router";
-import type { Issue, IssueLabel, IssueRelationIssueSummary, Project, WorkspaceRuntimeService } from "@paperclipai/shared";
+import type { Issue, IssueLabel, Project, WorkspaceRuntimeService } from "@paperclipai/shared";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { accessApi } from "../api/access";
 import { agentsApi } from "../api/agents";
@@ -197,21 +197,6 @@ function PropertyPicker({
   );
 }
 
-function IssuePillLink({
-  issue,
-}: {
-  issue: Pick<Issue, "id" | "identifier" | "title"> | IssueRelationIssueSummary;
-}) {
-  return (
-    <Link
-      to={`/issues/${issue.identifier ?? issue.id}`}
-      className="inline-flex max-w-full items-center rounded-full border border-border px-2 py-0.5 text-xs hover:bg-accent/50"
-    >
-      <span className="truncate">{issue.identifier ?? issue.title}</span>
-    </Link>
-  );
-}
-
 export function IssueProperties({
   issue,
   childIssues = [],
@@ -1146,7 +1131,7 @@ export function IssueProperties({
           <div>
             <PropertyRow label="Blocked by">
               {(issue.blockedBy ?? []).map((relation) => (
-                <IssuePillLink key={relation.id} issue={relation} />
+                <IssueReferencePill key={relation.id} issue={relation} />
               ))}
               {renderAddBlockedByButton(() => setBlockedByOpen((open) => !open))}
             </PropertyRow>
@@ -1159,7 +1144,7 @@ export function IssueProperties({
         ) : (
           <PropertyRow label="Blocked by">
             {(issue.blockedBy ?? []).map((relation) => (
-              <IssuePillLink key={relation.id} issue={relation} />
+              <IssueReferencePill key={relation.id} issue={relation} />
             ))}
             <Popover
               open={blockedByOpen}
@@ -1182,7 +1167,7 @@ export function IssueProperties({
           {blockingIssues.length > 0 ? (
             <div className="flex flex-wrap gap-1">
               {blockingIssues.map((relation) => (
-                <IssuePillLink key={relation.id} issue={relation} />
+                <IssueReferencePill key={relation.id} issue={relation} />
               ))}
             </div>
           ) : null}
@@ -1192,7 +1177,7 @@ export function IssueProperties({
           <div className="flex flex-wrap items-center gap-1.5">
             {childIssues.length > 0
               ? childIssues.map((child) => (
-                <IssuePillLink key={child.id} issue={child} />
+                <IssueReferencePill key={child.id} issue={child} />
               ))
               : null}
             {onAddSubIssue ? (