feat(agents): Add AGENTS.md file (#292)

Author: iambriccardo

AGENTS.md

@@ -0,0 +1,27 @@
+# Repository Guidelines
+
+## Project Structure & Modules
+- Rust workspace (`Cargo.toml`) with crates: `etl/` (core), `etl-api/` (HTTP API), `etl-postgres/`, `etl-destinations/`, `etl-replicator/`, `etl-config/`, `etl-telemetry/`, `etl-examples/`, `etl-benchmarks/`.
+- Docs in `docs/`; ops tooling in `scripts/` (Docker Compose, DB init, migrations).
+- Tests live per crate (`src` unit tests, `tests` integration); benches in `etl-benchmarks/benches/`.
+
+## Build and Test
+- Build: `cargo build --workspace --all-targets --all-features`.
+- Lint/format: `cargo fmt`; `cargo clippy --all-targets --all-features -- -D warnings`.
+
+## Coding Style & Naming
+- Rust 2024 edition; keep formatter clean and warnings denied.
+- Naming: crates `kebab-case`; files/modules `snake_case`; types/traits `CamelCase`; fns/vars `snake_case`.
+
+## Rust Docs Style
+- Document all items, public and private, using stdlib tone and precision.
+- Only use a "# Panics" section when a function can panic.
+- Link types and methods as [`Type`], [`Type::method`].
+- Keep wording concise, correct, and punctuated; reword for clarity while preserving intent.
+- No code examples; include private helpers for maintainers; apply to modules, types, traits, impls, and functions.
+
+## Rust Tests Execution
+- If output shows "0 passed; 0 failed; 0 ignored; n filtered out", tests did not run; treat as failure.
+- Common fixes: add features (`cargo test --all-features` or `--features <flag>`), pick the right target (`--lib`, `--bins`, `--tests`), verify integration vs unit layout, remove name filters, or run for the workspace (`cargo test --workspace`) or a specific crate.
+- Always verify actual execution: passed count > 0, test names appear, and counts match expectations.
+- Quick diagnostic: list available tests with `cargo test -- --list` before running.