.pmtiles files can be any unicode char but aws/cloudflare only accept S3 safe characters

In the AWS and Cloudflare proxy implementations we use a regex to parse the URL to a object storage key https://github.com/protomaps/PMTiles/blob/main/serverless/shared/index.ts#L8

This only allows S3-safelisted characters https://docs.aws.amazon.com/AmazonS3/latest/userguide/object-keys.html

But this means that if I have a valid but non safe listed filename我的城市.pmtiles in s3, then I put the lambda proxy in front, it will not work, it will return 404.

We should accept any character in URLs but be careful to avoid path traversal attacks, etc.

This also affects go-pmtiles and thus the GCP and Azure implementations: https://github.com/protomaps/go-pmtiles/blob/main/pmtiles/server.go#L441

Start with the regex in serverless/shared/index.ts and the handler around pmtiles/server.go:441, then trace how AWS, Cloudflare, GCP, and Azure implementations derive object-storage keys from URLs. Confirm the behavior for the Unicode filename example and define handling that accepts valid URL characters while rejecting path traversal; done means all affected proxies resolve such keys safely instead of returning 404.