resolve an Api's ApiResource directly from a DynamicObject/TypeMeta via Discovery

[jessemin]

Adds two convenience methods on Discovery to remove the boilerplate of going from a DynamicObject (or a bare TypeMeta) to its ApiResource/ApiCapabilities, so callers can build an Api without hand-assembling a GroupVersionKind.

pub fn resolve_typemeta(&self, tm: &TypeMeta) -> Option<(ApiResource, ApiCapabilities)>
pub fn resolve_object(&self, obj: &DynamicObject) -> Option<(ApiResource, ApiCapabilities)>

Both are thin wrappers over the existing GroupVersionKind::try_from(&TypeMeta) (kube-core/src/gvk.rs) and Discovery::resolve_gvk, so there's no new parsing/discovery logic — resolve_object just delegates to resolve_typemeta(obj.types.as_ref()?).

This follows the direction converged on in #1430 (resolve_typemeta as the general primitive that also enables custom dynamic types, resolve_object as the ergonomic wrapper for the motivating case), and keeps the surface on Discovery rather than adding an Api constructor.

Before:

let tm = object.types.as_ref().unwrap();
let gvk = /* split api_version, build GroupVersionKind ... */;
let (ar, _caps) = discovery.resolve_gvk(&gvk).unwrap();

After:
let (ar, _caps) = discovery.resolve_object(&object).unwrap();

Also adds a doc example on resolve_object (the TryFrom<&TypeMeta> impls are hard to discover in docs, per @nightkr's note).

Testing

• 4 unit tests covering resolve_typemeta/resolve_object (hit + miss + missing-TypeMeta), building a Discovery in-crate via ApiGroup::from_v2 + a mock client.
• cargo fmt, cargo clippy, doctest all clean.

Closes #1430

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.4%. Comparing base (8e6c86e) to head (845d5b2).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #2031     +/-   ##
=======================================
+ Coverage   77.3%   77.4%   +0.2%     
=======================================
  Files         89      89             
  Lines       9017    9054     +37     
=======================================
+ Hits        6965    7006     +41     
+ Misses      2052    2048      -4     

Files with missing lines	Coverage Δ
kube-client/src/discovery/mod.rs	73.7% <100.0%> (+25.5%)	⬆️

... and 6 files with indirect coverage changes

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