Release v0.6.0: Advanced monitoring and documentation restructure

### Added
- **📊 Prometheus Metrics Integration** (enabled by default)
  - PrometheusMetricsCollector with comprehensive job queue metrics
  - Built-in metrics: job counts, duration histograms, failure rates, queue depth, worker utilization
  - Custom gauge and histogram metrics support
  - HTTP exposition server for Prometheus scraping using warp

- **🚨 Advanced Alerting System** (enabled by default)
  - AlertingConfig with configurable thresholds for error rates, queue depth, worker starvation
  - Multiple notification targets: Webhook, Slack (with rich formatting), and email alerts
  - Cooldown periods to prevent alert storms
  - Background monitoring task for real-time threshold checking

- **📖 Comprehensive Documentation Restructure**
  - Restructured README from 677 to 124 lines (82% reduction)
  - Created detailed documentation subpages:
    - docs/quick-start.md - PostgreSQL and MySQL setup examples
    - docs/job-types.md - Job configuration, priorities, timeouts, cron jobs
    - docs/worker-configuration.md - Worker setup, rate limiting, statistics
    - docs/cron-scheduling.md - Recurring jobs with timezone support
    - docs/priority-system.md - Five-level priority system with weighted scheduling
    - docs/monitoring.md - Prometheus metrics and alerting systems

### Enhanced
- Optional feature flags: `metrics` and `alerting` (enabled by default)
- Background monitoring task for metrics collection and alerting
- Updated ROADMAP.md to remove completed features (metrics and alerting)
- Worker event recording now feeds both statistics and metrics collectors

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: CodingAnarchy

CHANGELOG.md

@@ -5,6 +5,45 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.6.0] - 2025-06-26
+
+### Added
+- **📊 Prometheus Metrics Integration** (enabled by default)
+  - `PrometheusMetricsCollector` with comprehensive job queue metrics
+  - Built-in metrics: job counts, duration histograms, failure rates, queue depth, worker utilization
+  - Custom gauge and histogram metrics support
+  - HTTP exposition server for Prometheus scraping using warp
+  - Real-time metrics collection integrated into worker event recording
+
+- **🚨 Advanced Alerting System** (enabled by default)
+  - `AlertingConfig` with configurable thresholds for error rates, queue depth, worker starvation, and processing times
+  - Multiple notification targets: Webhook, Slack (with rich formatting), and email alerts
+  - Cooldown periods to prevent alert storms
+  - Background monitoring task for real-time threshold checking
+  - Custom alert types and severity levels (Info, Warning, Critical)
+
+- **⚙️ Optional Feature Flags** 
+  - `metrics` feature flag for Prometheus integration (enabled by default)
+  - `alerting` feature flag for notification system (enabled by default)
+  - Backward compatible: existing users automatically get new features
+  - Opt-out available with `default-features = false` for minimal installations
+
+- **🔍 Background Monitoring**
+  - Automatic background task for metrics collection and alerting
+  - Queue depth monitoring every 30 seconds
+  - Worker starvation detection and alerts
+  - Statistics-based threshold monitoring
+
+### Changed
+- Default features now include `metrics` and `alerting` for enhanced monitoring capabilities
+- Enhanced worker integration with optional metrics and alerting components
+- Updated documentation with feature flag usage examples
+
+### Enhanced
+- Worker event recording now feeds both statistics collectors and metrics collectors
+- Thread-safe alerting with proper async handling and Send compatibility
+- Comprehensive test suite with 110 tests covering all features
+
 ## [0.5.0] - 2025-06-26
 
 ### Added

Cargo.toml

@@ -22,12 +22,15 @@ tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 async-trait = "0.1"
 tokio-test = "0.4"
 rand = "0.8"
+prometheus = { version = "0.13" }
+reqwest = { version = "0.12", features = ["json"] }
+warp = { version = "0.3" }
 
 [package]
 name = "hammerwork"
-version = "0.5.0"
+version = "0.6.0"
 edition = "2021"
-description = "A high-performance, database-driven job queue for Rust with PostgreSQL and MySQL support, featuring job prioritization, cron scheduling, timeouts, dead job management, and comprehensive statistics collection"
+description = "A high-performance, database-driven job queue for Rust with PostgreSQL and MySQL support, featuring job prioritization, cron scheduling, timeouts, rate limiting, Prometheus metrics, alerting, and comprehensive statistics collection"
 license = "MIT"
 repository = "https://github.com/CodingAnarchy/hammerwork"
 authors = ["CodingAnarchy <[email protected]>"]
@@ -50,11 +53,16 @@ thiserror = { workspace = true }
 tracing = { workspace = true }
 async-trait = { workspace = true }
 rand = { workspace = true }
+prometheus = { version = "0.13", optional = true }
+reqwest = { version = "0.12", features = ["json"], optional = true }
+warp = { version = "0.3", optional = true }
 
 [features]
-default = []
+default = ["metrics", "alerting"]
 postgres = ["sqlx/postgres"]
 mysql = ["sqlx/mysql"]
+metrics = ["prometheus", "warp"]
+alerting = ["reqwest"]
 
 [dev-dependencies]
 tokio-test = { workspace = true }