There's an albergue in Labruge. That's about 23 km from Porto. There's another about a km or so further along at Vila Chã (Albergue de S. Mamede). Both are well past the mid-way point, though, being only about 6 km or so from Vila do Conde.
For non-albergue accommodation, almost the entire stretch between Porto and Vila do Conde is one giant beach resort region. There are many accommodation options along that stretch, especially in private apartments / guest houses. The problem you might run into is that most want a minimum two night booking (especially during peak season). You need to look around a bit to find ones that will book only a single night.
Another option is to take the metro to Matosinhos and start from there. That makes the walk to Vila do Conde only about 21 km.