It means as you have suggested: ‘I didn’t find any mistakes at all.’ The word order for the verb is different ( verb-subject ‘did I’) because the sentence starts with the object in the negative. Other examples:
Not one person did I meet on my walk: I met no-one.
No special reason do I have for this comment. I have no reason.
This construction is used when you want to emphasise the object in the sentence - mistake/person/reason.
Well you have already understood the correct meaning of this sentence. But I want to give my angle.
If you just change this sentence as a question: [color=blue]Did I find a single mistake in your composition…? and if the answer is the first word ‘‘No(t)’’, then it is very clear that no single mistake was found in the composition.
This is new to me…because in my conceptual knowledge the word ‘‘any’’ can only be used for a single value.
(e.g)
in any [color=blue]situation, you must not lie…!
any[color=blue]way, please let me tell you what has happened actually…
there was no(t) any immediate medical [color=blue]help available to save the dog which was hit by a(n) over speeding car.
But in your contextual guidance, you mean the word ‘‘any’’ can be used for multiple values…(??)