The OpenAPI document describes feed interactions and sharing: POST /api/v1/feed/interactions and POST /api/v1/share #5313

For: the feed's two writes besides chips are in the contract, so a client can build the timeline from the document. #5156 covers feed, chips, asks and bulk decide; this is the rest of src/http/feed.ts except tells.

Done:

• [ ] POST /api/v1/feed/interactions (src/http/feed.ts:182) and POST /api/v1/share (src/http/feed.ts:272) each have a row. The row sits in ROUTES (src/contract/openapi.ts) beside its neighbours, with the request body, each answer and each refusal the handler actually returns; its line(s) leave NOT_YET_DESCRIBED in test/openapi-coverage.test.ts.
• [ ] A case in test/openapi-flow.test.ts (or a new test/openapi-oa-feed.test.ts) fails without them.

Files: src/contract/openapi.ts, test/openapi-coverage.test.ts, one test file. Risk: #5156 edits nearby rows; append yours in a separate block so either lands first.