[FEATURE] Bring "Group by: Project" filter (Code tab Recents) to Windows Desktop

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Issue #56067 ("Group recent sessions in sidebar by project / working directory") was closed as resolved. The resolution shown was a "Group by: Project" filter bar in the Code tab's Recents panel of Claude Desktop, with a dropdown for Date / Project / State / PR status / Environment / Custom groups (https://github.com/anthropics/claude-code/issues/56067#issuecomment-4502843130).
That UI does not exist in the Windows build. I'm on Claude Desktop 1.34493.1 (Windows), and every related issue I can find in this area (#56067, #57417, the sort-order bug on #56060) is tagged platform:macos — suggesting this shipped to macOS first with no Windows release, but there's no open issue tracking that gap. Because the original request reads as closed/resolved, it looks solved when it isn't for Windows users.
Without it, working across multiple projects means scanning a flat, recency-sorted Recents list to find which session belongs to which repo.

MACOS solution 56067 pictured:
<img width="1831" height="1004" alt="Image" src="https://github.com/user-attachments/assets/f01804ad-242f-4d7e-b14a-80d4fda4714d" />

Proposed Solution

Ship the existing "Group by: Project" filter bar (already built for macOS) to the Windows Code tab, so Recents can be grouped by project the same way shown in the #56067 demo video. No new design work should be needed — this is a platform-parity request, not a new feature design.

Alternative Solutions

Currently working around this with /rename (or --name at launch) to label sessions manually so they're distinguishable in the flat Recents list.
Doesn't scale past a handful of sessions and has to be redone every time.

Priority

High - Significant impact on productivity

Feature Category

Desktop app

Use Case Example

1. I'm running Claude Code across 4 active projects/repos at once (a job search system, a class project, etc.)
2. Each has multiple in-flight sessions (resume tailoring, interview prep, debugging, etc.)
3. On macOS, Group by: Project would let me collapse/expand each project's sessions instead of scrolling a mixed recency list
4. On Windows, I can't do this — I have to read session titles/paths one by one to find the right one, and it's easy to resume into the wrong repo

Additional Context

• Verified in the installed app bundle: none of the demo's UI strings ("Group by", "Sort by", "Custom groups", "Clear filters", "Last activity", "PR status") exist in app.asar for Claude Desktop 1.34493.1 (Windows).
• Related issues: #56067 (closed, original request), #57417 (Group by Project clone-collapsing bug, macOS), #56060 (sort-order bug, macOS).

Windows functionality (lack thereof) shown here:
<img width="606" height="285" alt="Image" src="https://github.com/user-attachments/assets/75e34b2b-beb1-433d-ae7d-2af369861fef" />