Module validation 

Queue validation submodule.

This module contains the validation entry points (validate_queue, validate_queue_set) plus internal helpers used to enforce queue invariants: ID formatting/prefix/width, required task fields, RFC3339 timestamps, and dependency correctness (existence + acyclic graph).

The parent queue module re-exports the public entry points so external callers can continue using crate::queue::validate_queue and friends.

Responsibilities:

• Validate queue file format, task fields, and dependencies.
• Detect hard errors (blocking) and warnings (non-blocking) for dependencies.

Not handled here:

• Queue persistence or modification (see crate::queue).
• Config file validation (see crate::config).

Invariants/assumptions:

• Task IDs are unique (within and across queue/done files, except for rejected tasks).
• Dependencies must form a DAG (directed acyclic graph).
• Warnings are collected but do not block queue operations.

Structs

DependencyValidationResult

Result of dependency validation containing both errors and warnings.

ValidationWarning

Represents a validation issue that doesn’t prevent queue operation but should be reported.

Functions

log_warnings

Log all validation warnings.

validate_queue

validate_queue_set

Validates a queue set (active + optional done file).