controller: browser_overlays + cookies field (Playwright session auth)

Use case: Grafana с session cookie (login flow вместо Bearer token),
admin UIs без API token endpoint.

Config:
  dashboards:
    - id: my_widget
      cookies:
        - name: session_id
          value: abc123
          url: https://example.com/

Каждый element passed к page.context.add_cookies. Playwright spec format:
{name, value, url} OR {name, value, domain, path, ...}.

Multi-dashboard verified рабочий (caвая dashboard = own Page в shared browser).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

controller/cuda_grid_controller/browser_overlays.py

@@ -73,6 +73,10 @@ class DashboardCfg(BaseModel):
         description="HTTP headers для каждого request — auth tokens, custom UA. "
                     "Пример Grafana service account: "
                     '{"Authorization": "Bearer glsa_xxxxxxxx"}')
+    cookies: list[dict] = Field(default_factory=list,
+        description="Session cookies через Playwright context.add_cookies. "
+                    "Каждый dict: {name, value, url}|{name, value, domain, path}. "
+                    "Пример: [{\"name\":\"session_id\",\"value\":\"abc\",\"url\":\"https://...\"}]")
     opacity: float = 1.0
     z_order: int = 28
 
@@ -137,6 +141,12 @@ class BrowserRenderer:
                 )
                 if cfg.extra_http_headers:
                     await page.set_extra_http_headers(cfg.extra_http_headers)
+                if cfg.cookies:
+                    try:
+                        await page.context.add_cookies(cfg.cookies)
+                    except Exception as e:
+                        log.warning("browser_overlays.cookies_invalid",
+                                    id=cfg.id, error=str(e))
                 # background_color в new_context не работает для transparent — used CLI arg
                 await page.goto(cfg.url, wait_until=cfg.wait_until,
                                 timeout=cfg.page_timeout_ms)