Add inline (token, factory) overloads to provides() and append()

[kburov-sc]

Stacked on #17.

Summary

Add inline (token, factory) and (token, deps, factory) overloads as alternatives to wrapping with Injectable():

Container.provides()

• provides('token', () => value) — zero-dep lazy factory
• provides('token', ['dep'] as const, (dep) => ...) — factory with type-checked dependencies
• Static Container.provides('token', () => value) entry point

Container.append()

• append('token', () => value) — zero-dep append
• append('token', ['dep'] as const, (dep) => ...) — append with dependencies

PartialContainer.provides()

• Same (token, fn) and (token, deps, fn) overloads with dependency tracking
• provides(PartialContainer) — compose partial containers
• provides(Container) — merge resolved services (satisfies existing deps)

PartialContainer.fromObject()

• Static factory to bootstrap from a plain object

Test plan

• npm test — 75 tests pass (13 new covering all new overloads + type errors)
• npm run styleguide — lint + prettier clean
• npm run compile — no type errors

🤖 Generated with Claude Code

[msilivonik-sc]

Love the change! Much simpler API in some cases!

[msilivonik-sc]

do you think never is a good feedback that we can provide to devs?

  const partial = new PartialContainer({})                  
    .provides("Foo", ["bar"] as const, (bar: string, extra: number) => bar)                                                                                                    
    .provides("Baz", () => "baz");  //  Property 'provides' does not exist on type 'never'

is there a way to make it better? maybe erroring on the factory function itself when parameter count doesn't match deps?

[kburov-sc]

Konstantin's AI agent: Fixed. Removed the conditional never return type — the error now only appears on the factory function via the ParamCountMismatch sentinel type (replaces void[] for a more readable compiler message). The next chained call compiles cleanly. Added @ts-expect-error regression tests to verify this stays correct.

[msilivonik-sc]

I see you added new ParamCountMismatch with some message, does this message expected to be part of compiler output? Check these examples:

1. this one is good:

2. this one is still cryptic:

It is def better then never, but maybe there is a way to improve that?

[kburov-sc]

Konstantin's AI agent: Good catch — the branded string intersection (string & { __brand: unique symbol }) caused TS to structurally expand comparisons against complex types like Date, listing all missing properties. Fixed by switching to an interface with a descriptive never property:

export interface ParamCountMismatch {
  readonly "Error: factory parameter count must match dependency count": never;
}

Now both cases produce the same clean error: Type 'ParamCountMismatch' is not assignable to type 'Date' — no property expansion. And hovering the type name in the IDE still shows the error message.

[msilivonik-sc]

LGTM! Left one question about compiler error message, but if it compilcates things a lot, then I guess you can ignore it.

[msilivonik-sc]

LGTM!

[msilivonik-sc]

LGTM!