Resolve Event Context Loss in Nested Event Cacnellation

[MohabCodeX]

Problem

When events trigger other events (nested), the parent event would lose its cancellation reason and context.

Solution

Replaced single event context pointer with a proper context stack, each event now maintains its own cancellation state and reason.

Results

Before

[08:30:50] [debug] [testing]\vbug\server.lua:28 - Testing nested events...
[08:30:50] [debug] [testing]\vbug\server.lua:21 - PASS: Event B has its reason
[08:30:50] [debug] [testing]\vbug\server.lua:12 - FAIL: Expected 'Reason A', got ''

After

[08:30:50] [debug] [testing]\vbug\server.lua:28 - Testing nested events...
[08:30:50] [debug] [testing]\vbug\server.lua:21 - PASS: Event B has its reason
[08:30:50] [debug] [testing]\vbug\server.lua:12 - PASS: Event A kept its reason

Testing script

addEvent("eventA", true)
addEvent("eventB", true)

addEventHandler("eventA", root, function()
    cancelEvent(true, "Reason A")
    triggerEvent("eventB", root)
    
    local reason = getCancelReason()
    if reason == "Reason A" then
        outputDebugString("PASS: Event A kept its reason")
    else
        outputDebugString("FAIL: Expected 'Reason A', got '" .. reason .. "'")
    end
end)

addEventHandler("eventB", root, function()
    cancelEvent(true, "Reason B")
    
    local reason = getCancelReason()
    if reason == "Reason B" then
        outputDebugString("PASS: Event B has its reason")
    else
        outputDebugString("FAIL: Expected 'Reason B', got '" .. reason .. "'")
    end
end)

addCommandHandler("testevent", function()
    outputDebugString("Testing nested events...")
    triggerEvent("eventA", root)
end)