docs: add ADR number references to module doc comments

New Phase 1 modules should follow the existing pattern of referencing
ADR numbers in module-level doc comments for discoverability, matching
the style in transport/mod.rs.

crates/alknet-core/src/auth/identity.rs

@@ -1,3 +1,8 @@
+//! Identity resolution and the `IdentityProvider` trait.
+//!
+//! See [ADR-029](docs/architecture/decisions/029-identity-provider.md) and
+//! [ADR-028](docs/architecture/decisions/028-identity-model.md).
+
 use std::collections::HashMap;
 use std::sync::Arc;
 

crates/alknet-core/src/call/mod.rs

@@ -1,3 +1,8 @@
+//! Call protocol layer (Layer 3) of the three-layer model.
+//!
+//! See [ADR-024](docs/architecture/decisions/024-call-protocol.md) and
+//! [ADR-033](docs/architecture/decisions/033-call-protocol-extensions.md).
+
 pub mod context;
 pub mod env;
 pub mod envelope;

crates/alknet-core/src/call/spec.rs

@@ -1,3 +1,8 @@
+//! Operation specifications (type, access control) for the call protocol.
+//!
+//! See [ADR-025](docs/architecture/decisions/025-operation-spec.md) and
+//! [ADR-033](docs/architecture/decisions/033-call-protocol-extensions.md).
+
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 

crates/alknet-core/src/config/config_service.rs

@@ -1,3 +1,7 @@
+//! Configuration service for runtime config reload.
+//!
+//! See [ADR-030](docs/architecture/decisions/030-dynamic-config.md).
+
 use std::sync::Arc;
 
 use arc_swap::ArcSwap;

crates/alknet-core/src/config/dynamic_config.rs

@@ -1,3 +1,7 @@
+//! Runtime-reloadable dynamic configuration (auth policy, forwarding policy, rate limits).
+//!
+//! See [ADR-030](docs/architecture/decisions/030-dynamic-config.md).
+
 use std::collections::HashMap;
 use std::sync::Arc;
 

crates/alknet-core/src/config/forwarding.rs

@@ -1,3 +1,7 @@
+//! Forwarding policy engine for per-identity and per-transport access control.
+//!
+//! See [ADR-031](docs/architecture/decisions/031-forwarding-policy.md).
+
 use std::net::IpAddr;
 use std::ops::Range;
 use std::str::FromStr;

crates/alknet-core/src/config/static_config.rs

@@ -1,3 +1,7 @@
+//! Static (immutable) server configuration resolved at startup.
+//!
+//! See [ADR-030](docs/architecture/decisions/030-dynamic-config.md).
+
 use crate::interface::InterfaceKind;
 use crate::server::handler::{ProxyConfig, ProxyMode};
 use crate::server::serve::{ListenerConfig, ServeTransportMode};