feat(api): align existing contracts for 0.8.0

[moonyue-w]

Summary

Align existing Forward and Managed API contracts with the official QCA documentation and prepare version 0.8.0. Covers generic Git resources, Template tool-round limits, Batch scheduling fields, Session search/outcomes/Thread statistics, Schedule provenance/input versions, native MemoryStore create-and-mount, setup scripts, MemoryStore/Dream metadata, and Managed artifact/error events.

Why

The existing public SDK types omit documented fields or require values that the API may omit. Requests now preserve the documented omission/null/false distinctions, and event history plus both SSE paths expose the new response fields. No new API endpoints are introduced.

Verification

• make lint/build/test, example build, check-version and 25 release automation tests passed. Full Go checks use an isolated copy of tracked source to exclude pre-existing ignored scratch code.
• Independent official-document fixtures cover request serialization, credential whitespace, nullable/absent responses and streaming variants. Python sync and async paths and TypeScript public types are covered.
• CN/Global integration against the installed QA packages will run on the merged SHA before formal release; results will be recorded in the release evidence.

Impact

• Public types, generated API references, contract fixtures, version files and changelog are updated together.
• Migration notes document null/absence semantics and diagnostic error codes; TypeScript consumers must handle nullable Skill versions and optional legacy Managed Thread usage.
• Go/Python/TypeScript scope is aligned. Credentials and live-test output are excluded from the commit.