I love that you know what you want, and Warlocks are flexible enough to accommodate, just keep in mind that if you insist on not taking one of the Melee routes, then it is harder to be as effective in melee.
But lets go with what you want: Archfey Patron, Pseudodragon, Melee fighter. Since you’ve already picked your Patron and Boon, you now have to choose your Race, spells and Invocations.
As a Melee fighter, you need a few things. First is proficiency in the weapon you want, second is a decent AC. You only get Light Armor and Simple Weapons from your class, so unless you are willing to just use a Quarterstaff, you need a Race that grants weapon proficiency. Elf or Dwarf is good. Human can work if you take a Feat, but using a Feat to grant proficiency in weapons is…well, not usually a good choice. But if you’re not doing Hexblade or Blade Pact, your only option if you don’t want to use Simple Weapons is a Race that grants the weapon you want.
As for AC, you have a few options. Light Armor can be fine if you’re going to max Dex, but it’ll only ever give you a 17 AC, and that’s with Dex maxed. You’ll be pretty easy to hit for most of your early and mid days. This is where an Invocation can help. Armor of Shadows basically gives you permanent Mage Armor, which is 13+Dex, basically giving you an 18 AC when your Dex is maxed. It’s better than Light Armor, but not as good as straight Medium with a Shield. The Medium Armor Feat gives you both of these, so Human Variant will give you those at lvl 1. Alternatively, you could wait until lvl 4 to grab that Feat, and it’s a Half ASI, so you are still getting one ASI point. If you use your race to get Weapon Proficiency, and your lvl 4 ASI to get the Moderately Armored Feat, then when you get a Breastplate, you’ll have an 18 AC, which is respectable. You could have a 19 if you can get Half Plate armor. And you’d only need a 14 Dex, giving you plenty of leeway to build your Charisma.
One more option for AC is at the expense of Martial Weapons, you could go Variant Human with the Moderately Armored Feat, then grab the Heavily Armored Feat at lvl 4, so you could use Plate Armor and Shields, giving you a full 20 AC. But you would be stuck with Simple Weapons. Not that this is necessarily bad, and that’ll be next.
The other thing is how to keep up with damage, and this is where your spells will help. Hex is a must. Green Flame Blade can work with any melee weapon, and add damage as you level up. One of them will be required to make this work, otherwise you’ll be done, at most, 1d8+dex damage, once a round, for your entire career. With Green Flame Blade, even a dagger can do decent damage, as all the bonus power comes from your spell, not the weapon. You will do a LITTLE less damage than if you used a longsword (1d4 vs 1d8), but the bonus damage would be the same. Because you will never get an Extra Attack, using the cantrip is the only way to be viable in combat.
My recommendation, after all this, is to take a Race that gives weapon Proficiency, then the Moderately Armored Feat at lvl 4 so you can use Shields. Here are a few options:
If you’re using a Rapier, be a Dark Elf, put a 15 in Dex to start so after racial’s you’ll have a 17 dex, then take Moderately Armored so you can put a point in Dex to bring it to 18 and then 20 at lvl 8, focusing on Charisma after that, or grabbing Medium Armor Master so you can increase your AC by 1, since you’ll have the Dex for it. You’ll also start with a 16 in Charisma, which isn’t bad.
If you’re using a longsword, go High Elf with a 15 in Str and a 12 in Dex so after Racials your Dex will be a 14, and when you get Moderately Armored, put 1 point in Str to bring it up to 16. You’ll have a 14 in Charisma, which is ok, but you’ll not be relying on Charisma spells for a good, long while.
If you want an axe, then go Hill Dwarf, put a 15 in Str which will give you a 17 after Racials, and a 14 in Dex, grab Heavily Armored at lvl 4 to bring Str up to 18, and then bring it to 20 at lvl 8. You’ll only have a 13 in Charisma, though. That’s what you give up for getting both Medium Armor and weapon proficiency in the race and getting Heavy Armor at lvl 4. But your AC will be a straight 18 with Plate Armor, which is nothing to sneeze at, and you’ll be able to use a two handed Axe for even more damage.
If you don’t mind using Simple Weapons, the best one is a Quarterstaff which is not a Finesse weapon, so go with Human variant with the Moderately Armored Feat, put Str at 15, bump it to 16 with Racials and 17 with Moderately Armored, grab Heavily Armored at lvl 4 to make it an 18, then push it to 20 by lvl 8. Put Charisma at 14, don’t worry about Dex at all with this build. Take Athletic as a skill to take advantage of your high strength. Don’t forget about Grapple, it can be a game changer if you do it right, and it’s an Athletics check. It’s similar to the Dwarf, except you have a 20 AC instead of 18, and your weapon damage suffers a little. So there’s a trade off.
As for Invocations, there are a few that will help with melee combat, but you’ll likely use them more for Out of Combat Utility. Armor of Shadows is a waste, since I think you should just use Medium Armor. But Misty Visions, casting Silent Image at will, can be amazing. Voice of the Chain Master is a given. Cloak of Flies at lvl 5 does Charisma Damage to anyone standing next to you, and you can have it up indefinitely if you want(if you don’t mind having flies buzzing around you at all times). Maddening Hex and Relentless Hex are also good for extra damage. They all key off Charisma, so better for the Dark Elf, but if you wind up playing to higher levels, you’ll wind up with a 20 in Charisma in almost all of these builds eventually.
As for spells, Hex is important, and Armor of Agathys is amazing for defense. Besides those two, go to town. Experiment. You have combat taken care of, so don’t be afraid of taking utility spells. Don’t forget with all these builds, Charisma suffers until higher levels, so some spells will be better than others.
And lastly, don’t forget about your Patron abilities and the Pseudodragon. Use the familiar to grant Advantage on everything, let it scout ahead and trip traps for you, and see if your DM will let you harvest its poison. And with an Archfey, you can charm or frighten once a day.
You COULD start as a Fighter or something to gain proficiencies and armor. One level of Fighter means you can grab Heavy Armor and any weapon you want for any race you want. You just need a 15 str for Plate Armor, and your set. Dump dex, boost Str and Cha, and go to town. You could even do Variant Human, Heavy Armor Master, put 15 in Str, +1 from racials, +1 from HAM for a total starting str of 17, then just boost Str and Cha with your ASI’s. But I wanted to look at options for a pure warlock, because there is something to be said at actually getting your higher level abilities and spells when you’re supposed to.
