* Fix all golangci-lint issues across the codebase
Resolve 77 lint issues reported by golangci-lint with gocritic, gocognit,
gocyclo, maintidx, dupl, mnd, unparam, ireturn, goconst, and errcheck
enabled. Net reduction of ~175 lines through shared helpers and
deduplication.
* Suppress staticcheck SA1019 for intentional deprecated field usage
The Storage.Path field is deprecated but still read for backwards
compatibility with existing configs that haven't migrated to the URL field.
All handler metadata and proxy requests were using http.DefaultClient directly,
bypassing any timeout or transport configuration. Added an HTTPClient field to
the Proxy struct with a 30-second default timeout, and updated every handler
to use it for upstream HTTP requests.
POST endpoints (/api/outdated, /api/bulk) now reject bodies over 1 MB
using http.MaxBytesReader. Upstream metadata reads (npm, pypi, composer,
nuget, pub) now use io.LimitReader capped at 50 MB to prevent OOM from
unexpectedly large responses.
Hides package versions published too recently from metadata responses,
giving the community time to spot malicious releases. Configurable
per-ecosystem and per-package with duration overrides. Supported for
npm, PyPI, pub.dev, and Composer.
