[BUG] [RMF Roles] - 'Assign RMF Roles' chat quick-action button fires but opens no modal — silent regression from #584

## Bug Description
The "Assign RMF Roles" quick-action button in the chat panel (on the system detail / overview page) no longer opens a modal or any UI interaction. Clicking the button produces no visible response — the page simply remains as-is. No modal, no error, no loading state.

This is a **regression** from the behavior described in issue #584 (where the modal opened but showed "No Person components found in Component Library"). The modal no longer appears at all.

## Steps to Reproduce
1. Navigate to `https://ca-ato-copilot-dashboard-v2.../systems/92afdc15-bc6f-4648-8073-ad6af396cf97`
2. In the chat sidebar, locate the "👤 Assign RMF roles" quick-action button
3. Click it
4. Observe: nothing happens — page stays static

Also occurs when clicking the "👤 Assign RMF roles" button in the Phase Readiness checklist section.

## Expected Behavior
A modal or workflow should appear to assign RMF roles (ISSO, ISSM, AO, SCA, SystemOwner, MissionOwner) to the system.

## Actual Behavior
- No modal appears
- No error message
- No loading state
- Page does not change

## Relates To
- Supersedes / regression from: #584 "Assign RMF Roles modal blocked: 'No Person components found in Component Library'"

## Screenshot
[Captured: Overview page with RMF Phase Progress showing "RMF Roles Assigned ✅" but Assign button still present and non-functional in chat sidebar]

## Console Errors
No JavaScript errors observed in console.

## Browser/Environment
Azure Container Apps Dashboard (v2)
Browser: Chromium (Playwright/Hermes browser)
Date: 2026-07-06
Sweep: Automated 4-hour QA sweep

## Playwright Test Code
```typescript
test('[rmf-roles] assign modal opens from chat quick-action', async ({ page }) => {
await page.goto('/systems/92afdc15-bc6f-4648-8073-ad6af396cf97');
await page.click('button:has-text("Assign RMF roles")');
await expect(page.locator('[role="dialog"]')).toBeVisible(); // FAILS — no dialog appears
});
```

*Filed by Oracle — Automated 4-hour QA Sweep 2026-07-06T07:43:00Z*