fix(defaulted): skip factories when their defaults cannot be used

[FanWu-ai]

The documented defaulted(number(), () => i++) ID generator advances even when an ID was supplied and its fallback is discarded. Creating {id: 42} followed by {} assigns the generated ID 1 rather than 0. A valid supplied value also throws when its unused default factory throws.

Return supplied values before evaluating fallbacks when strict mode is enabled or the input is not a plain object. Undefined input still evaluates once. Non-strict plain objects still evaluate the fallback because its properties may need merging. The wrapped struct's own coercer still executes.

Validation on Node 24.19.0 and 22.19.0:

• Fresh complete baseline: 225 tests; final: 233, with full CJS/ESM build and both TypeScript projects passing.
• Required configured lint/whole-project Prettier and supplemental direct changed-file ESLint pass.
• Exact new tests on original source: 6 failures / 2 controls.
• 4,028 independent assertions per runtime and 1,934 additional review cases pass, covering generated IDs, throwing factories, strict/object merging, non-plain/null-prototype values, result/reference parity and underlying trimming.

The reused dependencies retain an existing expect 29.7 compatibility resolution for wildcard @types/expect; no dependency change is made here, and a fresh unpinned CI install may differ. Other runtimes and hosted checks are not claimed passed. Prepared and tested with AI assistance (OpenAI Codex); no human review is claimed.