Core domain logic for Agent Assembly.

This crate is no_std compatible and contains the foundational types, traits, and pure logic shared across all other crates in the workspace. It has no runtime or I/O dependencies.

Feature Flags

• std (default): enables std-dependent convenience impls (e.g. From<SystemTime>)
• alloc: enables heap types (String, Vec, BTreeMap) in no_std environments
• serde: enables Serialize/Deserialize derives on all core types (added in AAASM-22–25)
• test-utils: exposes PermitAllEvaluator and DenyAllEvaluator for downstream test code
• std (also default): enables CredentialScanner and all std-dependent types
• alloc (also default via std): enables AuditEntry, AuditEventType, and all audit types