Release Plan Dashboard: Make summary status counts clickable to filter results

## Problem

The Release Plan Dashboard (https://aka.ms/azsdk/releaseplan-dashboard) displays summary counts at the top of the page:

- **Total** (e.g., 186)
- **In Progress** (e.g., 60)
- **Partially Released** (e.g., 30)
- **New / Not Started** (e.g., 26)
- **Finished in last 2 months** (e.g., 8)

These numbers are purely informational. To find plans in a specific status, users must scroll through the grouped sections below. When there are 60+ In Progress plans spread across planes, this is cumbersome.

## Proposed Solution

Make each summary count a clickable element that filters the view to show only release plans in that status.

## Acceptance Criteria

- [ ] Each status count (Total, In Progress, Partially Released, New/Not Started, Finished in last 2 months) is clickable
- [ ] Clicking a count filters the card list to show only plans matching that status
- [ ] The active/selected filter is visually indicated (e.g., underline, highlight, bold border)
- [ ] Clicking "Total" or clicking the currently active filter clears the status filter (shows all)
- [ ] Status filter composes with existing Plane/Month/Type filters

## UX Suggestion

Consider styling the counts as tab-like buttons or adding hover states to indicate they are interactive. The current large colored numbers already draw the eye — making them clickable is a natural affordance.

Start at the Release Plan Dashboard linked in the issue and locate the summary status counts and existing Plane/Month/Type filters. Implement clickable status filtering with a visible active state, filter composition, and reset behavior for Total or the active filter; verify each acceptance criterion in the dashboard.

Written by the indexing model from the issue text.