Simplify safe output handler architecture - remove special case for project handlers

[Copilot]

Fixes temporaryIdMap.get is not a function error in update_project by simplifying the handler architecture so all handlers work uniformly.

Root Cause

The original implementation had project handlers receiving different parameters than regular handlers, creating unnecessary complexity. The reviewer correctly identified that all handlers should work with resolvedTemporaryIds (plain object).

Changes

• Unified handler signature: All handlers (project and regular) now receive (message, resolvedTemporaryIds) - no special Map parameter
• Removed special cases: Eliminated isProjectHandler tracking and conditional branching
• Simplified retry logic: All deferred messages are retried with the same parameter pattern
• Backward compatibility: Made internal functions support both Map and plain object during transition
• Updated tests: Removed expectations of Map mutation since handlers return temporary ID mappings instead

// Before: Project handlers received special treatment
if (isProjectHandler) {
  result = await messageHandler(message, temporaryIdMap, resolvedTemporaryIds);
} else {
  result = await messageHandler(message, resolvedTemporaryIds);
}

// After: All handlers receive the same parameters
result = await messageHandler(message, resolvedTemporaryIds);

Result

• ✅ Cleaner, more maintainable architecture with no special cases
• ✅ All handlers read from resolvedTemporaryIds and return temporary ID mappings
• ✅ Unified handler manager treats all message types consistently
• ✅ All 3,400 JavaScript tests pass

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[mnkiefer]

@copilot Draft issue items should also work with resolvedTemporaryIds. There should be no need for an extra case of the handler

[Copilot]

@copilot Draft issue items should also work with resolvedTemporaryIds. There should be no need for an extra case of the handler

You're absolutely right! I've simplified the architecture so all handlers (both project and regular) work the same way:

• All handlers now receive (message, resolvedTemporaryIds) - no special Map parameter for project handlers
• Handlers read from resolvedTemporaryIds (plain object) and return temporary ID mappings
• The unified handler manager treats all handlers uniformly - no more isProjectHandler branching

This makes the code cleaner and removes the unnecessary special case. All 3400 tests pass. (commit e7d00e7)