I won't try to define 'foreign invader', I just think it was obvious to the people that there was an aggressor state plundering their territory.
You're imposing 19th century conceptions of state and nation onto the 15th century, which simply does not work. There were no nations to bestow the large-scale abstract collectivism upon territory that you suggest, so there's no reason to assume that characteristically modern sentiments would be found among a pre-modern populace. "Our land" is a concept that would only be found in communes and in clans, and both of those were intensely local identities (and the latter irrelevant to France).
I think it is an exaggeration that over a hundred years this was still just a squabble of competing dunasties, with no sentiments among the peasants and townspeople.
The townspeople, perhaps, but not the peasants; those were, at the time, too hugely disparate demographics. Furthermore, that the middle classes may have leant support one way or the other- as indeed they did- does not suggest that this support was necessarily nationalistic. Rather, it was based on a mixture of tradition and pragmatism, and often coming down to what was most advantageous for the local economy. (One town or region might favour the Plantagenets, for example, because a nearby economic rival had the favour of the Valois.)
Even Normandy, the origin of the Plantagenets, usually supported the French crown against England. Henry V had to conquer it all over again in 1415.
In what sense does that suggest popular support one way or the other? It was a war, not an election. Regime change was easier in feudal Europe than it was under almost any other system: all you needed to do was remove a previous lord and walk into his place, and life continued for the vast majority much as it had always done. This wasn't like the Norman conquest of England, in which an entire ruling class, social structure and body of law were being violently torn out, it was simply the institution of individuals for individuals.
And, again, there was no "French crown" and "English crown", there were rival claimants to the French crown. Both the Plantagenets and Valois laid claim to the French crown, the Plantagenets additionally claiming the English, while the Valois saw the English king as a vassal of the French.
Yea splitting hair over wether the invader was foreign misses the point. There was a war and they accepted her because they needed somone to believe in at the time.
But the very notion of "they", as in "the French people", assumes a national struggle, which is exactly what I am arguing was absent.