[P2.1-T02] Add RuleMetadata struct

[RichardHightower]

Task: Add RuleMetadata struct

Phase: 2.1 - Core Governance
Estimated: 0.5 day
File: cch_cli/src/models/mod.rs

Description

Create the RuleMetadata struct to support rule provenance tracking.

Acceptance Criteria

• Create RuleMetadata struct in models/mod.rs
• Fields: author, created_by, reason, confidence, last_reviewed, ticket, tags
• All fields are Option<T>
• Create Confidence enum: High, Medium, Low
• Implement Deserialize and Serialize
• Add unit tests

Code Reference

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct RuleMetadata {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub author: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub created_by: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub reason: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub confidence: Option<Confidence>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub last_reviewed: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub ticket: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tags: Option<Vec<String>>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum Confidence {
    High,
    Medium,
    Low,
}

[RichardHightower]

Completed in PR #72