refactor: consolidate TLS helpers — move LoadGatewayTLS from server into httputil

[Copilot]

TLS helpers were scattered across three packages: internal/httputil (protocol-level helpers), internal/proxy (self-signed cert generation), and internal/server (LoadGatewayTLS). The server placement was wrong — LoadGatewayTLS has no server-package dependencies and is consumed only by internal/cmd.

Changes

• Move LoadGatewayTLS → internal/httputil/tls.go alongside NewServerTLSConfig (which it calls), consolidating all file-loading and protocol-level TLS helpers in one package
• Delete internal/server/gateway_tls.go; update internal/cmd/root.go to call httputil.LoadGatewayTLS
• Relocate tests to internal/httputil/tls_gateway_test.go as package httputil_test (external test package avoids the httputil ← proxy ← httputil import cycle)
• Update package-level comments in httputil/tls.go and proxy/tls.go to accurately describe the two-package split
• Remove stale logger-namespace exception for the deleted file

Resulting package responsibilities

Package	Owns
internal/httputil	MinTLSVersion, NewServerTLSConfig, NewClientTLSConfig, ConfigureTLSTrustEnvironment, LoadGatewayTLS
internal/proxy	GenerateSelfSignedTLS — self-signed cert generation, proxy-specific

[Copilot]

Pull request overview

Consolidates gateway TLS loading in internal/httputil without changing behavior.

Changes:

• Moves LoadGatewayTLS and its tests from server to httputil.
• Updates callers, documentation, and logger namespace exceptions.

Show a summary per file

File	Description
internal/server/gateway_tls.go	Removes relocated TLS loader.
internal/httputil/tls.go	Adds gateway TLS loading.
internal/httputil/tls_gateway_test.go	Relocates TLS loader tests.
internal/cmd/root.go	Uses the relocated helper.
internal/proxy/tls.go	Updates TLS responsibility documentation.
internal/logger/logger_namespace_test.go	Removes the obsolete exception.

Review details

Tip

Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

• Files reviewed: 6/6 changed files
• Comments generated: 0
• Review effort level: Medium