Read the Prebid EID cookie in the Prebid crate

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- **Breaking for crates outside core:** the identifiers a request carries come from identifier modules. Core declares `IdentifierModule` in `trusted_server_core::ec::identifiers`, a registration offers one with `IntegrationRegistrationBuilder::with_identifier_module`, and core asks every running module once per request, when it reads the Edge Cookie state, then syncs the answers to the identity graph and carries them to the auction as it did the `ts-eids` cookie. The Prebid module owns that cookie, its two shapes and its size limit, and is the first identifier module. `COOKIE_EIDS` is removed from core, `ec_finalize_response` no longer takes the cookie's value, `EcContext::module_eids` holds what the modules learned, and `RuntimeServices` carries the modules through `with_identifier_modules`. A `template_cache_key_cookies` entry naming any cookie under the public prefix is refused, where the Edge Cookie and the EIDs cookie were refused by name. A deployment's settings do not change.
 - **Breaking:** The React Server Components Flight rewriter is the middleware `framework.nextjs.flight` of the Next.js module, which runs on a `text/x-component` response where a `[[fetch]]` entry names it, where core rewrote every Flight response by media type. A deployment that fronts a Next.js site selects `[framework] module = "nextjs"` and adds the entry, as `trusted-server.example.toml` shows it. With the module selected and no entry, a Flight response passes through as the origin sent it, and an entry may now cover `text/x-component`. A middleware says with `Middleware::moves_origin_address` that it moves the origin's address itself, and core then leaves the addresses in a body of the media types it handles to it, whether or not an entry names it, because a plain replacement in a length prefixed row leaves the old length. **For crates outside core**, `trusted_server_core::rsc_flight` is removed.
 - **Breaking:** Where content comes from is a source module. `[source]` selects the publisher's, and each `[[proxy.asset_routes]]` entry selects its own in a `source` table of the same shape, with `module` naming the source and its settings in the table beneath. Core supplies `origin`, an HTTP origin, and a module a build links can offer another through `IntegrationRegistrationBuilder::with_source_module`. A source answers for each request where that request's content comes from, and core fetches, caches, rewrites the origin host and follows the redirect rule from that answer. `[source]` is required. The origin settings move into the `origin` table, and a document that still writes one where it was is refused at startup naming the new place. An environment variable that set the address is now `TRUSTED_SERVER__SOURCE__ORIGIN__URL`. The old name is refused where the build reads variables, and `ts config push` ignores it, as it ignores any variable for a key the document does not hold. A path in an asset route's `url` names a folder the target path is added under, where a path was refused, a target path with a `.` or `..` segment under a folder is answered `400`, and a route applies `directory_index` as the publisher does. Stored pages and the publisher's stored assets are fetched again after the upgrade, because their keys hold a code worked out from the settings, but an asset route's stored copies keep their keys. Where `host_header` is set, the page pipeline and every middleware are now told that `Host` as the page's origin host, where they were told the address's host, so the page's own addresses under that name are rewritten to the request's host. **For crates outside core**, `handle_asset_proxy_request` takes the route's source, which `IntegrationRegistry::route_source` gives, and `Publisher::origin_host`, `origin_host_header` and `origin_query_is_stripped` are replaced by `Settings::origin_source` and the `SourceLocation` a source answers.