Simplify lifetime management

[Mr3zee]

Strict mode Migration
A series of changes to simplify kRPC protocol

• Remove fields support
• Remove stream scopes
• Simplify lifetime management
• Cold RPC clients creation
• Deprecated declarations cleanup
• Documentation update for previous changes

Subsystem
kRPC

Problem Description
Lifetimes now have a hierarchy. We decided to abandon this approach.

Solution
Remove complex hierarchy of requests.
One of the side effects:

• Service on client-server are now 1-to-n instead of 1-to-1.

[Copilot]

Pull Request Overview

This PR simplifies lifetime management in the kRPC protocol by removing the complex inheritance hierarchy and related fields. Key changes include:

• Eliminating inheritance from CoroutineScope in RpcServer and RpcClient while updating the service factory signatures.
• Deprecating and removing the RemoteService interface along with its coroutineContext-related properties.
• Removing support code that auto-injects RemoteService as a supertype, including associated compiler plugin components.

Reviewed Changes

Copilot reviewed 193 out of 193 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
core/src/commonMain/kotlin/kotlinx/rpc/annotations/Rpc.kt	Removed explicit RemoteService inheritance from annotated interfaces and updated sample code.
core/src/commonMain/kotlinx/rpc/RpcServer.kt	Changed serviceFactory signature and removed CoroutineScope inheritance; documentation remains outdated.
core/src/commonMain/kotlinx/rpc/RpcClient.kt	Removed CoroutineScope and Deferred usage; documentation still refers to CoroutineScope lifetime.
core/src/commonMain/kotlinx/rpc/RemoteService.kt	Deprecated the RemoteService interface and removed its CoroutineScope dependency.
core/api/core.api	Updated API definitions to reflect removed coroutine context parameters.
Compiler plugin files	Removed several supertype generator files and updated diagnostic messages and checkers accordingly.
compiler-plugin/compiler-plugin-backend/src/main/core/kotlinx/rpc/codegen/extension/RpcStubGenerator.kt	Removed coroutineContext property generation from RPC stub code.
Remaining compiler-plugin files	Adjusted references to removed properties and methods related to lifetime/coroutineContext.

Comments suppressed due to low confidence (2)

core/src/commonMain/kotlin/kotlinx/rpc/RpcServer.kt:14

• The documentation comment still mentions [CoroutineScope] defines server lifetime, but RpcServer no longer extends CoroutineScope. Please update the comment to reflect the current lifetime management approach.

 * Server may contain multiple services. [CoroutineScope] defines server lifetime.

core/src/commonMain/kotlin/kotlinx/rpc/RpcClient.kt:17

• The documentation comment for RpcClient still refers to CoroutineScope for defining its lifetime, but the interface no longer extends CoroutineScope. Please update the comment accordingly.

 * [CoroutineScope] defines the lifetime of the client.