Implement consistent lock ordering in ApplicationManager

[sfloess]

Part of #423: Race condition potential in ApplicationManager concurrent operations

Problem

Multiple methods in ApplicationManager acquire locks in different orders, creating potential for deadlock. When methods acquire per-application locks and the global applications map lock in inconsistent order, two threads can each hold one lock while waiting for the other.

Location

• platform-core/src/main/java/org/flossware/platform/core/ApplicationManager.java

Tasks

• Audit all lock acquisition sites in ApplicationManager
• Define a canonical lock ordering (e.g., global map lock before per-application lock)
• Refactor all methods to follow the canonical ordering
• Add comments/javadoc documenting the lock ordering contract

Acceptance Criteria

• All methods that acquire multiple locks do so in the same documented order
• No deadlock possible between any two concurrent method calls