feat(config): add optional database connection CLI args

[coderdan]

Adds optional command line args to proxy for specifying the database, host and username.
If not provided, env and config is used as now.
If running in docker this has no effect but is very useful if running the binary directly.

Acknowledgment

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[Copilot]

Pull Request Overview

This PR adds optional command line arguments for database connection parameters (host, name, and username) to the CipherStash proxy. These CLI arguments provide an alternative to environment variables and configuration files for specifying database connection details when running the proxy binary directly.

• Adds new CLI arguments: --db-host, --db-name, and --db-user
• Refactors the TandemConfig::build method to accept an Args struct instead of just a file path
• Updates all test cases to use the new build_path convenience method

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/cipherstash-proxy/src/cli/mod.rs	Adds three new optional CLI arguments for database connection parameters
packages/cipherstash-proxy/src/config/tandem.rs	Refactors config building to accept Args struct and handle CLI overrides; adds build_path convenience method
packages/cipherstash-proxy/src/config/database.rs	Adds default username function with serde annotation
packages/cipherstash-proxy/src/proxy/mod.rs	Updates test to use new build_path method
packages/cipherstash-proxy/src/config/log.rs	Updates all tests to use new build_path method
packages/cipherstash-proxy-integration/src/migrate/mod.rs	Updates Args struct initialization with new CLI fields

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[freshtonic]

A change with a clear benefit and it's fairly simple too. Nice one @coderdan.

[auxesis]

Love this, thanks for the PR @coderdan — big usability improvement.

Could you add something to docs/reference/index.md explaining how to start Proxy with these new command line options?

Looking forward to taking this for a spin. ❤️