fix(go): support tls connections and validate over tls

[Mandukhai-Alimaa]

What's Changed

This PR fixes TLS handling and updates the validation to test self-signed TLS.

• Make SSLVerification=NONE and SSLCertPath work correctly with the custom client and avoid TLS config leaking across connections.
• Run the validation over TLS

[Copilot]

Pull request overview

This PR updates the Go Trino driver’s TLS handling (custom HTTP client + TLS config) and extends the Go validation environment/tests to exercise HTTPS against a self-signed local Trino Docker setup.

Changes:

• Add per-connection custom HTTP client registration with explicit TLS configuration (trusted CA and “skip verification” modes).
• Update Python URI validation tests/fixtures to construct HTTP/HTTPS URIs and validate TLS scenarios (including self-signed CA).
• Extend local Docker Compose setup/scripts/config to expose HTTPS (8443) and generate/mount TLS assets.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
go/validation/tests/trino/test_uri.py	Updates URI/DSN tests to use username-only auth and to validate multiple SSL/TLS modes (trusted CA, skip verify, plain HTTP).
go/validation/tests/trino/conftest.py	Reworks fixtures to build URIs/DSNs from environment variables and support HTTP/HTTPS ports + cert path.
go/validation/README.md	Adds pre-build step and documents HTTPS TRINO_DSN example for self-signed CA usage.
go/db_factory.go	Implements TLS-aware custom HTTP client creation/registration and prevents TLS settings from leaking via config fields.
go/compose.yaml	Exposes 8443 and mounts Trino HTTPS config + generated keystore/CA cert into the container.
go/ci/scripts/pre-build.sh	New script to generate a local self-signed CA + PKCS#12 keystore for the Docker HTTPS setup.
go/ci/docker/trino/config.properties	Enables HTTPS alongside HTTP in the local Trino container and points to the mounted keystore.
go/ci/docker/certs/openssl-server.cnf	OpenSSL server certificate config (SANs for localhost/127.0.0.1) used to generate the keystore.
go/ci/docker/certs/openssl-ca.cnf	OpenSSL config for generating the self-signed CA cert used for local trust.
go/.gitignore	Ignores generated TLS artifacts (ca.crt, localhost.p12).
go/.env.linux	Switches validation defaults to HTTPS (8443) and adds TRINO_SSL_* env vars used by URI-specific tests.

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[lidavidm]

Were you able to replicate the original issue?

[Mandukhai-Alimaa]

I tested the driver with a self-signed certificate and found an issue. This PR fixes it, but the error I saw was different from the original issue. The original error showed "schema does not exist," which I suspect may be a downstream effect of this bug. I asked the reporter to try a local build after the PR is merged. If the error persists, I will investigate further.