Upstream sync: 39 new commits (2026-03-24) #19

4088739 [Node] Add Commands and UI Elicitation Support to SDK (#906)
7463c54 [Python] Remove `copilot.types` (#871)
5ecfc94 Update CHANGELOG for v0.2.0 release
1ff9e1b Update @github/copilot to 1.0.10 (#900)
005b780 Add fine-grained system prompt customization (customize mode) (#816)
a124096 fix: Go codegen enum prefixes and type name reconciliation (#883)
d82fd62 fix(dotnet): handle unknown session event types gracefully (#881)
7390a28 [python] Refactor `CopilotClient.create_session()` and `resume_session()` to have parameters (#587)
01208ca Remove unnecessary docs
fb67979 fix(nodejs): add CJS compatibility for VS Code extensions (#546)
2b01b61 On branch edburns/java-readme-add-maven-g-a Make the Java row more like the other rows. (#889)
0fbe0f6 Go: stop RPC client logging expected errors (#609)
21504ac Fix justfile install 585 (#634)
1a94402 detach cli lifespan from the context passed to Client.Start (#689)
3e443fe Fix serialization of SessionEvent (#868)
d96488c [Python] Declare various modules as private (#884)
2bfbb47 Add experimental API annotations from schema stability markers (#875)
698b259 feat: add blob attachment type for inline base64 data (#731)
dde88fb Add Permission Handling documentation to all language READMEs (#879)
7d8fb51 Add official Java SDK information to README (#876)