Tracking modernisation of parameter and dependency specification

[provinzkraut]

Tracking issue for the progress of migrating away from old-style parameter / dependency declaration patterns.

Goals

• No implicit declarations. All parameters in handlers and DI must declare their source
• No declarations of metadata in function parameter defaults. All metadata must be declared in the parameter annotation using Annotated or an Annotated alias

PRs

• feat(core): Introduce explicit parameter declarations with generics #4750
• feat(core): Introduce generic request body markers #4801
• feat(di): Deprecate params.Dependency, introduce di.NamedDependency and params.SkipValidation #4808
• chore(core)!: Remove deprecated params.Dependency and params.DependencyKwarg #4818
• feat(core)!: Remove deprecated function parameter default declarations for metadata #4819
• feat(core)!: Remove implicit parameter definitions #4799
• feat(core): Deprecate request "reserved kwargs" #4817
• feat(core): Deprecate implicitly declared dependencies #4824