fix(parser): restore Bilibili b23.tv short-link redirects

[goxofy]

Summary

• restore parsing for Bilibili App share links using b23.tv short URLs
• accept Resty's expected ErrAutoRedirectDisabled sentinel so the parser can inspect the first redirect response and extract its Location header
• add deterministic, proxy-backed regression tests for successful redirects, missing locations, invalid redirect targets, transport errors, and direct BVID URLs

Root cause

The proxy-support migration changed Bilibili short-link handling from net/http with http.ErrUseLastResponse to Resty's NoRedirectPolicy().

Both approaches intentionally stop automatic redirects so the parser can manually read Location. However, net/http returns the intercepted response without an error, while Resty returns resty.ErrAutoRedirectDisabled together with the response. The existing Bilibili parser treated that expected Resty sentinel as a request failure before reading Location.

Validation

• go test ./parser/ -run 'TestBiliBiliGetBvidFrom' -count=1
• go test ./... -count=1
• go vet ./...
• go test -race ./parser/... -count=1
• verified the supplied public b23.tv share link through the CLI end to end

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