[Frontend] Add browser privacy controls for analytics and session replay

## Problem
Health, location, wallet, and emergency flows require stronger guarantees that analytics or session-replay tooling cannot capture sensitive fields.

## Scope
Add a data-classification-aware telemetry wrapper, consent gating, and automated DOM redaction checks.

## Acceptance criteria
- No analytics event is emitted before consent where consent is required.
- Inputs, text, URLs, wallet addresses, pet identifiers, health values, and maps are excluded or masked by default.
- Emergency and authentication pages opt out of session replay entirely.
- Consent withdrawal stops future collection and clears queued events.
- Tests assert payload redaction and opt-in/opt-out behavior.

Start by locating the frontend telemetry, analytics, session-replay, consent, and existing test entry points. Verify that sensitive DOM and payload data are excluded or masked, collection follows consent, protected pages opt out, and withdrawal clears queued events; automated tests should assert these behaviors.

Written by the indexing model from the issue text.