Persist approved web follow-ups in Ambiguous

[jerelvelarde]

Web follow-ups currently disappear on refresh. This change lets the assistant prepare an Ambiguous task for review, saves it only when the user approves the exact fields in the page, and reads the provider record back after saving or reloading.

The integration preserves the simplified incident UI and the merged React Native runtime. Proposals expire after ten minutes and are bound to the browser session and workspace identity. Approval metadata is stored locally; saved tasks come from Ambiguous. The web agent cannot bypass the page approval through raw MCP write tools. Development and production start commands bind to loopback, with the resulting mobile device setup documented.

Validation at 06e0415:

• Clean install, root typecheck and local verification pass. The web suite has 34 passing tests covering approval/denial, persistence/readback, session and workspace binding, expiry, concurrent approval, uncertain writes, provider failures and cleanup errors.
• Web production build passes, including the web approval and mobile runtime routes. The existing Google Vertex dynamic import warning remains.
• Independent review found and fixed a provider cleanup failure that could mask the response; both successful and failed requests have regression coverage.
• Fresh live OpenAI/Ambiguous validation passed: page context and native card, exact proposal approval, provider readback, persistence in a fresh browser page, assistant retrieval, and decline without a write.
• A deliberately invalid provider credential produced a sanitized pre-write error; restoring configuration allowed the same proposal to save exactly one matching task. An unchanged proposal was rejected after its actual ten-minute expiry, with no write attempt or provider task. This tests pre-write authentication failure, not an uncertain failure after sending a write. Ambiguous returned no record URL; the UI displayed its actual ID without inventing a link.

Slack completion is tracked independently in #8. The deferred WhatsApp work is preserved separately in #9.