Search cassette

Reference pages for Search cassette, synced at build time from papercomputeco/search-cassette. Each page is owned by that repo, so a behavior change and its documentation land in the same pull request there.

• Search cassette — Semantic span search over the tapes read model, with the embedding pass that keeps it current.
• API reference — The span search endpoint, the MCP tool over the same operation, the result shape, and status codes.
• Embedding — The embed pass that keeps the span projection searchable — how it selects work, how it handles failure, and the metrics it exposes.
• Deploying — The image, its configuration, the embedding providers it supports, and the database objects a deployment must provision.
• Development — Build and test from a checkout, how the module relates to tapes, and what the test suite pins.