feat(profiles): SDK methods and docs for entity profiles

Adds the profile surface to both SDKs and documents it.

Python (MemoryClient + AsyncMemoryClient) and TypeScript gain:
get/generate profile, get/update settings, sample, regenerate.

A profile's keys come from the customer's own JSON Schema, so the TS
client keeps `profile` opaque and passes `schema` through untouched in
both directions. Camel-casing them would return field names that do not
match the schema the customer wrote.

Reads use the v2 envelope, where a known entity with no profile yet is a
200 carrying a status rather than a 404, so an empty state is
distinguishable from an error.

Verified against a live environment running this API: settings
round-trip, a partial update leaves the schema intact, generation
produces a profile under the configured schema, and sample, regenerate,
cooldown and the 400/404 paths all answer as documented.

docs/api-reference/profiles/get-profile.mdx

@@ -0,0 +1,5 @@
+---
+title: 'Get Profile'
+description: "Retrieve the structured profile for a user or agent, with a status describing whether generation has completed."
+openapi: get /v2/entities/{entity_type}/{entity_id}/profile/
+---