fix(redis): use spread operator for variadic Redis set operations

[sylvesterdamgaard]

Summary

This PR contains two important improvements:

1. Fixes critical bug causing throughput_per_minute and avg_duration_ms metrics to always show 0
2. Restructures documentation for PHPeek.com compliance

Problem (Redis Bug)

The addToSet() and removeFromSet() methods in RedisMetricsStore were passing arrays directly to PhpRedis sadd() and srem() methods, which expect variadic arguments. This caused Redis to store the literal string "Array" instead of actual job identifiers in discovery sets.

Impact

• Job discovery sets contained invalid data
• listJobs() returned empty arrays
• CalculateAggregatedJobMetricsAction always returned 0 for all metrics
• Queue throughput and duration metrics were completely broken

Root Cause

Before:

$this->getRedis()->sadd($key, $members);  // ❌ Passes entire array
$this->getRedis()->srem($key, $members);  // ❌ Passes entire array

After:

$this->getRedis()->sadd($key, ...$members);  // ✅ Spreads array as variadic args
$this->getRedis()->srem($key, ...$members);  // ✅ Spreads array as variadic args

Changes

Redis Fix

• src/Support/RedisMetricsStore.php:175 - Added spread operator to addToSet() method
• src/Support/RedisMetricsStore.php:193 - Added spread operator to removeFromSet() method

Documentation Restructure

• Add frontmatter (title, description, weight) to all documentation files
• Create introduction.md as main landing page (replaces README.md)
• Organize into basic-usage/ and advanced-usage/ sections with _index.md
• Update all internal links to use relative paths without .md extension
• Set logical weight-based ordering for navigation
• Move files to appropriate sections:
  • basic-usage/: facade-api, api-endpoints, artisan-commands
  • advanced-usage/: architecture, events, prometheus, performance
• Remove duplicate README.md from docs folder

The documentation now properly displays on PHPeek with correct SEO metadata, navigation hierarchy, and user-friendly organization.

Test Plan

• Unit tests pass (124/125 passing)
• Manual testing: Jobs are now properly discovered
• Manual testing: throughput_per_minute calculates correctly (was 0, now shows actual values)
• Manual testing: avg_duration_ms calculates correctly (was 0, now shows actual values)
• Verified discovery sets store proper job identifiers instead of "Array" string
• Regression testing: No existing functionality broken
• Documentation structure verified for PHPeek compliance

Test Coverage

• Existing test suite for RedisMetricsStore operations
• Integration tests for job metrics calculation
• Discovery set population tests

Verification

Before Fix:

Discovered jobs: 0
throughput_per_minute: 0
avg_duration_ms: 0

After Fix:

Discovered jobs: 1
  - App\Jobs\FastJob
    Total processed: 5
    Total duration: 36702.52 ms
    
throughput_per_minute: 5
avg_duration_ms: 7340.50

Related Issues

The Redis bug was present since the initial implementation of the Redis discovery sets feature.