fix: provider sub-aspect functions receive parametric context

[sini]

Fixes #413

Problem

Provider sub-aspects defined as bare context functions don't receive { host } during resolution:

den.aspects.foo._.sub = { host, ... }: {
  nixos = lib.optionalAttrs (host.hostName != "whatever") {
    networking.networkmanager.enable = true;
  };
};

When a parent function returns { includes = [foo._.sub] }, the sub-aspect is resolved by the adapter system which only passes { class, aspect-chain } — the { host } context from the pipeline never reaches nested includes of function results.

Fix

applyDeep in parametric.applyIncludes — when takeFn succeeds and returns a bare result with sub-includes (no meta, no __functor), also apply takeFn to those sub-includes. This propagates context to provider sub-aspects nested inside function results without double-applying to parametric wrappers or deepRecurse outputs.

The key discriminator: bare provider results carry only includes (+ name from carryAttrs). Results from withOwn/withIdentity have meta; deferred deepRecurse wrappers have __functor. Neither should be re-resolved.

Test coverage

• deadbugs/issue-413-provider-bare-function.nix — reproduces the original report
• deadbugs/issue-413-provider-sub-aspect-function.nix — variant with lib.optionalAttrs guard
• provides-parametric.nix — provider sub-aspects with parametric context in various configurations

cc: @kalyanoliveira for the report

[vic]

Thanks @kalyanoliveira and @sini