visual_analyze URL mode: network lost / timeout across attempts

[stackbilt-admin]

Summary

visual_analyze fails when called with a url parameter. The screenshot_id parameter mode works fine (returns clean structured findings from Llama 4 Scout). Almost certainly cascades from the broken URL → screenshot code path in visual_screenshot (see companion issue).

Repro

```json
// Input
{ "url": "https://imgforge.stackbilt.dev", "page_id": "imgforge-landing" }

// Attempt 1 response
{ "error": "Visual QA error: Network connection lost." }

// Attempt 2 response (same payload, minutes later)
{ "error": "Visual QA error: The operation was aborted due to timeout" }
```

Two different failure modes on identical payload = the URL handler is either flaky, has a non-deterministic bug, or is trying a broken downstream (the visual_screenshot URL path).

The screenshot_id path works

```json
// Input
{ "screenshot_id": "21d2094b-40c9-4b89-b430-a9f0c180ba63" }

// Response
{
"analysis_id": "a145bec6-4d47-40a4-962a-99236433ba44",
"severity": "critical",
"summary": "...",
"findings": [...],
"model": "@cf/meta/llama-4-scout-17b-16e-instruct"
}
```

Clean 200, structured findings, correct model attribution. The analysis pipeline itself works — it's purely the URL-driven entry that's broken.

Root cause (suspected)

visual_analyze with url probably delegates to visual_screenshot internally to capture the page, then runs the vision model. Since visual_screenshot URL mode is non-functional (companion issue), the cascade fails upstream before analysis runs.

Proposed fix

Once the visual_screenshot URL path is fixed, re-test this. If it still fails, this handler has its own downstream bug. Add:

1. Explicit error mapping so callers see "SCREENSHOT_CAPTURE_FAILED" instead of raw "Network connection lost".
2. A timeout/retry on the internal screenshot call so transient failures don't bubble as Aborted due to timeout.

Severity

Medium. URL mode is the more discoverable entry (simpler than pre-screenshotting). Workaround exists via screenshot_id.

Companion

See visual_screenshot URL-mode issue on this repo. Fix together.

[stackbilt-admin]

Companion: #35 — visual_screenshot URL mode. Fix #35 first, then confirm this resolves automatically.