Promote service modules to services/ directory; add AmqpConnection + async IPL

- Flat src/amqp.rs, src/mongo.rs, src/mariadb.rs promoted to src/services/{amqp,mongo,mariadb}/
- services/amqp/connection.rs: AmqpConnection struct with connect() and declare_exchange()
- services/amqp/error.rs: AmqpError type (thiserror, wraps lapin::Error)
- ipl() made async; #[tokio::main] added to main()
- IPL step 3b: authenticate to RabbitMQ + declare beds.events topic exchange (durable)
- Added lapin = "2" and tokio = { version = "1", features = ["full"] } to Cargo.toml
- 12 unit tests pass
- Docs: README, CLAUDE.md, wiki/04-ipl.md, wiki/06-queue-topology.md updated

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -85,26 +85,33 @@ Every node runs the same binary. Configuration determines what it does.
 rustybeds/
 ├── src/
 │   ├── config/
-│   │   ├── mod.rs          # Loader — load() and load_from() for testability
-│   │   └── structs.rs      # Typed config structs (serde Deserialize)
-│   ├── amqp.rs             # RabbitMQ transport — validate(), future channel/queue ops
-│   ├── mariadb.rs          # MariaDB transport — validate_all(), future adapter ops
-│   ├── mongo.rs            # MongoDB transport — validate_all(), future adapter ops
-│   ├── lib.rs              # Public API surface for integration test harness
-│   ├── logging.rs          # tracing + journald init
-│   └── main.rs             # ipl() sequence + main()
+│   │   ├── mod.rs              # Loader — load() and load_from() for testability
+│   │   └── structs.rs          # Typed config structs (serde Deserialize)
+│   ├── services/
+│   │   ├── mod.rs              # Groups external service transport modules
+│   │   ├── amqp/
+│   │   │   ├── mod.rs          # validate() — TCP reachability pre-flight
+│   │   │   ├── connection.rs   # AmqpConnection — auth + exchange declare
+│   │   │   └── error.rs        # AmqpError type
+│   │   ├── mongo/
+│   │   │   └── mod.rs          # validate_all() — TCP reachability
+│   │   └── mariadb/
+│   │       └── mod.rs          # validate_all() — master/secondary pattern
+│   ├── lib.rs                  # Public API surface for integration test harness
+│   ├── logging.rs              # tracing + journald init
+│   └── main.rs                 # async ipl() sequence + #[tokio::main] main()
 ├── config/
-│   ├── beds.toml           # Base config — checked in, no credentials
-│   ├── env_dev.toml        # Dev overrides — gitignored
-│   ├── env_qa.toml         # QA overrides — gitignored
-│   └── env_prod.toml       # Prod overrides — gitignored
+│   ├── beds.toml               # Base config — checked in, no credentials
+│   ├── env_dev.toml            # Dev overrides — gitignored
+│   ├── env_qa.toml             # QA overrides — gitignored
+│   └── env_prod.toml           # Prod overrides — gitignored
 ├── templates/
-│   ├── example_rec.toml    # Canonical self-documenting REC template
-│   └── mst_logger_rec.toml # Logger collection template (msLogs)
+│   ├── example_rec.toml        # Canonical self-documenting REC template
+│   └── mst_logger_rec.toml     # Logger collection template (msLogs)
 ├── tests/
-│   ├── common/mod.rs       # Shared test helpers — load_test_config()
+│   ├── common/mod.rs           # Shared test helpers — load_test_config()
 │   └── fixtures/
-│       └── beds_test.toml  # Canonical test config fixture
+│       └── beds_test.toml      # Canonical test config fixture
 └── Cargo.toml
 ```
 
@@ -138,11 +145,12 @@ The `config` crate deep-merges these at startup. Only keys present in the env fi
 | Structured logging (journald + console mirror) | Done |
 | IPL sequence with env-aware error handling | Done |
 | RabbitMQ reachability validation | Done |
+| RabbitMQ authentication + exchange declaration | Done |
 | Unit test scaffolding + config fixture pattern | Done |
 | MongoDB reachability validation | Done |
 | MariaDB reachability validation | Done |
-| Shared filesystem validation | Next |
-| AMQP channel / queue declaration | Planned |
+| Broker pool (Tokio tasks) + queue declaration | Next |
+| AMQP publish / consume | Planned |
 | Broker pool (Tokio tasks) | Planned |
 | NamasteCore trait | Planned |
 | Database adapters (MariaDB, MongoDB) | Planned |