feat(social-controllers): add intent and category fields to Trade type

[Bigshmow]

Explanation

Add intent ("enter" | "exit") as the preferred alternative to the semi-deprecated direction field, and category (optional) to distinguish trade types (e.g. "receive" for airdrops/transfers).

TSA-371

References

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
Updates the Trade contract and superstruct validation to require a new intent field and restrict direction/intent to enums, which may break consumers or reject older API responses that don’t include these fields.

Overview
Extends the Trade model to include required intent ('enter' | 'exit') and optional category, and narrows direction to 'buy' | 'sell'.

Moves the trade validation schema into social-types as exported TradeStruct, derives Trade via Infer, and updates SocialService position validation and tests to use the new schema.

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