[WIP] URGENT: Memory leak in diagnosticbench-app-202504091010 causing 500 errors and downtime

[Copilot]

• Analyzed codebase and identified memory leak sources
• Built and verified application compiles successfully
• Fix event subscription memory leak in PublisherSubscriber.cs (2.1GB leak from 2,100 subscribers with 1MB each)
• Fix static references preventing garbage collection in AppController.cs
• Remove duplicate CreatePublishers() call in Program.cs
• Add proper disposal patterns and reduce memory allocation
• Test memory leak fixes
• Verify application functionality remains intact

Root Cause Analysis:

1. Primary Issue: Subscriber.CreatePublishers() creates 2,100 subscribers, each holding 1MB byte array (line 15: new byte[1024 * 1024]) with event subscriptions that never get unsubscribed (line 19), causing ~2.1GB permanent memory retention
2. Secondary Issues: Static references in AppController (Processor p, memoryHog) prevent garbage collection
3. Duplicate Calls: CreatePublishers() called both in Program.cs (line 30) and AppController.cs (line 17), doubling the memory leak

Memory Impact: Matches production incident showing 1.36GB in System.Byte[] with 1722 objects and GC root chains preventing cleanup.

Fixes #35.

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