Add a plugin API for reading HTTP response bodies

Plugins read bodies by response id through ctx.httpResponse.body()
instead of opening HttpResponse.bodyPath themselves. The accessors are
named after fetch's, minus the single-use semantics, since the bytes are
durable and re-reading should work.

Underneath is a chunked pull over the existing plugin protocol, so the
host can move bodies off the filesystem without plugins noticing.
text() now decodes with the response's charset rather than assuming
UTF-8, and the buffering accessors refuse past 32 MiB and point at
chunks().

packages/plugin-runtime-types/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@yaakapp/api",
-  "version": "0.8.0",
+  "version": "0.9.0",
   "keywords": [
     "api-client",
     "bruno-alternative",