feat: Bridge quotestream token warning events

[infiniteflower]

Explanation

The bridge-api SSE quote stream (getQuoteStream) now emits token_warning events alongside quote events. These warnings come from Blockaid security scanning of the destination token and contain information like whether a token is a honeypot or has unstable pricing.

Previously, fetchBridgeQuoteStream ignored the SSE event: name and attempted to validate every message as a quote response. This meant token_warning events were silently dropped (or caused spurious validation failures).

This PR:

• Adds event routing in fetchBridgeQuoteStream — only quote events go through quote validation, token_warning events are validated separately via a new superstruct schema and routed to a dedicated handler, and all other event types are skipped.
• Adds a tokenWarnings: TokenFeature[] field to BridgeControllerState, populated from the SSE stream and cleared on reset / new quote fetch.
• Renames onValidationFailure to onQuoteValidationFailure and #trackResponseValidationFailures to #trackQuoteValidationFailures for clarity now that there are multiple event types.
• Exports TokenFeature type and TokenFeatureType enum for use by clients.

References

• Related to bridge-api token warning implementation in va-mmcx-bridge-api-1

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Medium Risk
Changes the SSE quote-stream parsing/handlers and BridgeControllerState, which can affect quote loading behavior and downstream consumers that assume only quote events or a fixed state shape.

Overview
Adds support for token_warning events in the bridge-api SSE quote stream by routing events by event: name in fetchBridgeQuoteStream (quotes are validated/processed separately from warnings).

BridgeControllerState now includes tokenWarnings, which is reset on new quote requests and resetState, populated via a new onTokenWarning stream handler, and exposed via new exported TokenFeature/TokenFeatureType types. Quote validation failure handling is renamed to onQuoteValidationFailure/#trackQuoteValidationFailures, and tests/snapshots are updated with a warning-capable SSE mock.

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