fix: configure self-hosted S3 CORS for presigned uploads (#3379)

[ansaftab-1]

Problem

In self-hosted Puter deployments, browser file uploads fail with a CORS policy error when sending PUT requests to S3 presigned URLs on RustFS (s3.<domain>). The browser issues an HTTP OPTIONS preflight request prior to the upload, but because the bucket was created without a bucket-level CORS policy, RustFS does not return the required Access-Control-Allow-* headers.

Fixes #3379

Solution

1. Automated Bucket CORS Policy (docker-compose.yml):

   • Updated the s3-init service to pass PUTER_DOMAIN and PUTER_PROTOCOL.
   • s3-init writes and applies a bucket-level CORS configuration allowing origins for ${PUTER_PROTOCOL}://${PUTER_DOMAIN} and its subdomains (api, app, site, dev, host).
   • Configured AllowedMethods: ["GET", "HEAD", "PUT", "POST", "DELETE"], AllowedHeaders: ["*"], ExposeHeaders: ["ETag", "x-amz-request-id"], and MaxAgeSeconds: 3600.
   • Applied via aws --endpoint-url "$endpoint" s3api put-bucket-cors.

2. Idempotent Initialization:

   • If the bucket already exists (head-bucket succeeds), s3-init does not exit early; it proceeds to apply/update the CORS policy so existing installations receive the fix without data loss.

3. Installer Support (install.sh & install.ps1):

   • Updated install.sh and install.ps1 to write PUTER_DOMAIN and PUTER_PROTOCOL to .env.
   • Updated install.ps1 to accept -PuterProtocol parameter and dynamically configure protocol and publicEndpoint in config.json.

4. Documentation:

   • Documented PUTER_DOMAIN and PUTER_PROTOCOL in doc/self-hosting.md and .env.example, including HTTPS setup instructions.

5. Testing:

   • Added automated test suite (tools/test-s3-cors.mjs) validating default HTTP domain origins, custom HTTPS domain origins, allowed methods/headers, absence of wildcard origins, simulated browser OPTIONS preflights, idempotency logic, and installer consistency.

Tests Run

• node tools/test-s3-cors.mjs: 20/20 tests passed.
• git diff --check: Passed with 0 whitespace errors.
• sh -n install.sh: Passed with exit code 0.
• PowerShell AST parser validation of install.ps1: Passed with 0 errors.
• PyYAML validation of docker-compose.yml: Passed with exit code 0.

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[Salazareo]

hi @ansaftab-1 could you please sign CLA