test(mcp): await fetches in network tests to fix flake

[yury-s]

Summary

• The filter and stable indexes network tests fired fetches from inline <script> tags and immediately checked browser_network_requests, racing the responses.
• Moved the fetches into browser_evaluate so the call resolves only after they complete.

[github-actions]

Test results for "MCP"

13 failed
❌ [firefox] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-windows-latest-firefox
❌ [firefox] › mcp/cli-devtools.spec.ts:231 › video-chapter @mcp-windows-latest-firefox
❌ [firefox] › mcp/cli-json.spec.ts:177 › close-all after open returns closed sessions @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:124 › daemon show: closing page exits the process @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:165 › should capture annotations via show --annotate @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:186 › should start dashboard and annotate when no dashboard is running @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:208 › should enter annotate mode on fresh dashboard.tsx mount with annotate @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:232 › should annotate via direct browser_annotate MCP call @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:265 › should cancel browser_annotate when the MCP request is aborted @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:296 › should cancel browser_annotate when the MCP client disconnects @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:325 › should switch screencast to -s session on show --annotate @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:374 › should disengage annotate mode when --annotate client disconnects @mcp-windows-latest-firefox
❌ [firefox] › mcp/dashboard.spec.ts:441 › save recording streams WebM bytes to the chosen file @mcp-windows-latest-firefox

6850 passed, 1015 skipped

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Merge workflow run.