feat(core): initialize alknet-core crate with module skeleton

Create crates/alknet-core with Cargo.toml (dependencies, feature flags
quinn/iroh), src/lib.rs declaring types/auth/config/endpoint modules, and
skeleton files for each module with doc comments and TODO markers. Add the
crate to the workspace members list.

Both quinn (default-on) and iroh (opt-in) are optional and can be active
simultaneously per ADR-010. Dual license MIT OR Apache-2.0 inherited from
the workspace.

Cargo.toml

@@ -1,6 +1,7 @@
 [workspace]
 members = [
     "crates/alknet-vault",
+    "crates/alknet-core",
 ]
 resolver = "2"
 

crates/alknet-core/Cargo.toml

@@ -0,0 +1,32 @@
+[package]
+name = "alknet-core"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+description = "Core library for ALPN-based protocol dispatch: ProtocolHandler trait, Connection, auth, config, and multi-connectivity endpoint"
+repository.workspace = true
+
+[lib]
+name = "alknet_core"
+
+[features]
+default = ["quinn"]
+quinn = ["dep:quinn"]
+iroh = ["dep:iroh"]
+
+[dependencies]
+tokio = { version = "1", features = ["full"] }
+quinn = { version = "0.11", optional = true }
+iroh = { version = "0.35", optional = true }
+rustls = "0.23"
+rustls-pki-types = "1"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+toml = "0.8"
+arc-swap = "1"
+async-trait = "0.1"
+tracing = "0.1"
+thiserror = "2"
+zeroize = { version = "1", features = ["derive"] }
+bytes = "1"
+futures = "0.3"

crates/alknet-core/src/auth.rs

@@ -0,0 +1,6 @@
+//! Authentication: `AuthContext`, `Identity`, `IdentityProvider`, `AuthToken`,
+//! `ConfigIdentityProvider`.
+//!
+//! See `docs/architecture/crates/core/auth.md` for the full specification.
+
+// TODO: implement

crates/alknet-core/src/config.rs

@@ -0,0 +1,6 @@
+//! Configuration: `StaticConfig`, `DynamicConfig`, `AuthPolicy`, `ApiKeyEntry`,
+//! `RateLimitConfig`, `ConfigReloadHandle`, `ConfigError`, `TlsIdentity`.
+//!
+//! See `docs/architecture/crates/core/config.md` for the full specification.
+
+// TODO: implement

crates/alknet-core/src/endpoint.rs

@@ -0,0 +1,5 @@
+//! Endpoint: `AlknetEndpoint`, `HandlerRegistry`, `EndpointError`.
+//!
+//! See `docs/architecture/crates/core/endpoint.md` for the full specification.
+
+// TODO: implement

crates/alknet-core/src/lib.rs

@@ -0,0 +1,12 @@
+//! alknet-core: Core library for ALPN-based protocol dispatch.
+//!
+//! Every handler crate depends on this crate. It provides the
+//! [`ProtocolHandler`][crate::types::ProtocolHandler] trait, the
+//! [`Connection`][crate::types::Connection] wrapper, auth primitives,
+//! hot-reloadable configuration, and the [`AlknetEndpoint`][crate::endpoint::AlknetEndpoint]
+//! that dispatches incoming QUIC connections by ALPN string.
+
+pub mod auth;
+pub mod config;
+pub mod endpoint;
+pub mod types;

crates/alknet-core/src/types.rs

@@ -0,0 +1,6 @@
+//! Core types: `ProtocolHandler`, `HandlerError`, `Connection`, `BiStream`,
+//! `SendStream`, `RecvStream`, `StreamError`, `Capabilities`.
+//!
+//! See `docs/architecture/crates/core/core-types.md` for the full specification.
+
+// TODO: implement