Present Tense – ‘I Already Know’ vs ‘I Have Already Known’

I believe you're thinking of the passive voice construction, or of the perfect construction (which is variously called an "aspect" or a "tense"). Both of these constructions use the past participle form of a verb, and the past participle of the verb make is "made".

The perfect construction doesn't generally use forms of "to be" in modern English; it's made using a form of the verb "to have" + a past participle.

The passive voice does use a form of the verb "to be" + a past participle. However, it is not a type of past tense. In any case, "Windows are made of glass" is not a passive-voice sentence: most people would do a double-take if you responded to this sentence with a question like "By whom?" or "Who does this?"

The word "made" in this sentence is not a participle, but an adjective. See the definition in Collins' Advanced English Dictionary:

adjective If something is made of or made out of a particular substance, that substance was used to build it.

The structure of the predicate is just "are," the simple present plural form of "be", followed by the predicative adjective phrase "made of glass".

There are a number of adjectives like "made" that look exactly like past participles. So some sentences are ambiguous between "be + predicative adjective" (active voice) and "be + past participle" (passive voice). Usually the context resolves any confusion. In this case, a general statement about the composition of windows (active voice) seems more likely than a passive-voice statement.

Another relevant question about this topic: How to identify whether the sentence is in passive voice or Simple past (state)

The use of the simple present tense indicates that a statement applies now.

The use of a modifier such as always or never indicates that the statement it modifies universally applies (always) or doesn't ever apply (never). It is usually used to indicate that the statement relates to a habitual or reoccurring state or action.

When different tenses are used with the modifiers always and never, subtly different meanings are implied.

• The simple past tense indicates that the statement applied at all times in the past, or that it universally applies and the past is the most relevant reference point to your statement. It can be used to imply that the statement no longer applies, especially if used with before. E.g. It always did that before. = at all occasions in the past it did something (that), but on the most recent occasion(s) it has stopped doing "that". Universal application can be inferred from context, it is usually used with never and often means that the point at which it could have happened has passed. E.g. I never climbed Everest. = At no point in the past did I climb Everest, and implies that the point at which I could have climbed Everest has passed, so I will also not climb Everest in the future.
• The simple present indicates that it applies at all times in the past and present. It can imply future continuation, but does not necessitate it. E.g. It always does that. = it currently does "that" and did "that" at all times in the past. It implies that it will probably continue to do "that", but leaves the possibility that it may stop doing "that".
• The simple future indicates that it applies at all points in the future, and it usually indicates that it applies at all times past, present and future (but it may not necessarily). E.g. I will never climb Everest = I have not yet climbed Everest, and I will not climb it in the future. If you include the adverb "again" with never, it means that it occurred previously, but will not occur in future. E.g. I will never climb Everest again = I have climbed Everest, but I will not climb it in the future.

So in your example, I never know implies that the situation has come up before, repeatedly, and Harry has not previously known, and still doesn't know.