Add memoryservice with in-memory implementation. (#89)

Commit: 4f35d0e

Date: September 9, 2025 at 12:48 PM

Reflects

https://github.com/google/adk-python/tree/e45c3be23895b5ec68908ad9ee19bd622dcbd003/src/google/adk/memory

It currently operates with session.Session. I'd follow up regarding the

use-cases for Session vs StoredSession and update if needed in future

PR.

Inmemory implementation is based on the 2-level map: {appName, userID} ->

sessionID -> {event + eventWords}

eventWords is a precomputation to fetch based on the read request words.

gitv1