feat(tools): add soroban multi-network config loader, tests, CLI verifier, and docs

[OthmanImam]

Closes: #4

Summary

Adds a deterministic, strongly-typed Soroban network configuration system that resolves the
active network from environment variables and soroban.toml profiles, with clear error
handling, unit tests, and a small CLI verifier.

Files changed

• Added: soroban.toml
• Added: .env.example
• Added: crates/tools/src/config.rs (typed loader, errors, and tests)
• Updated: crates/tools/Cargo.toml (deps)
• Updated: crates/tools/src/main.rs (CLI network command)
• Updated: README.md (docs snippet)

What it does

• Implements Config::load() with resolution order:
  1. Environment variables: SOROBAN_NETWORK, SOROBAN_RPC_URL, SOROBAN_NETWORK_PASSPHRASE
  2. Profile selected in soroban.toml (testnet, mainnet, sandbox, or custom)
  3. Fail with typed ConfigError when ambiguous or missing required values
• Provides Network enum and a strongly-typed Config struct for use by deployment
  scripts and tests.
• CLI verifier: cargo run -p stellaraid-tools -- network prints:
  • Active network:
  • RPC URL:
  • Passphrase:

Tests & verification

Included unit tests under crates/tools:

• loads_profile_by_name — profile resolution (testnet)
• env_overrides_profile_values — env vars override profile
• missing_required_values_returns_error — fails with typed error if required values missing
• loads_sandbox_profile — sandbox profile

Run locally:

cargo test -p stellaraid-tools
cargo run -p stellaraid-tools -- network

Rationale

• Keeps this crate focused on resolving and exposing effective configuration; relies on the
  official Soroban CLI for editing/managing soroban.toml.
• Uses dotenvy, serde + toml, and thiserror for robust parsing and structured errors.
• Tests isolate environment loading to avoid flakiness and ensure determinism.

Notes for reviewer

• The loader searches upward from the current working directory for soroban.toml.
  If a .env file sits adjacent to the chosen soroban.toml, it will be loaded (allowing
  project-local .env overrides).
• .env.example contains no secrets and documents override behavior.
• No configuration editing commands were added (per design decision).

Commit

• 27335be — feat(tools): add soroban multi-network config loader, tests, CLI verifier, and docs

Next steps

To push and open a PR:

git push -u origin feat/Network
# then open a PR on GitHub with this description