For the court-bouillon: Prepare a large pot of boiling water (about 8 quarts). To the water, add the lemon halves, garlic, thyme, coriander seeds, bay leaves, salt and wine. Bring the pot back to a boil, then add the lobster and cook until bright red, 10 minutes. Remove the lobster from the water and set aside to cool.
When cool enough to handle, remove the tail, claw and knuckle meat and reserve the shells and bodies. Keep 2 pieces of claw meat whole and reserve. Slice 1 tail lengthwise into 4 pieces and reserve. Dice the remaining tail into large chunks along with the remaining claw meat and knuckle meat. Set aside.
For the risotto: Warm the chicken stock in a saucepan over medium-low heat. Add the reserved lobster shells and bodies to the stock.
Heat the olive oil in a large, heavy-bottomed saucepan over medium-high heat. Add the onion, season with kosher salt and a pinch of crushed red pepper and saute until the onions are translucent, 5 minutes. Add the rice and stir to coat with the olive oil and onion. Toast the rice, stirring frequently, for 2 to 3 minutes. Add the wine, tomatoes and a pinch of salt and stir frequently until the liquid has completely absorbed.
Begin to add the hot stock, two ladlefuls at a time. Stir frequently until the stock has absorbed into the rice. Add the saffron. Repeat adding the stock two more times until the rice is tender but still has some bite to it. There may be leftover stock. Add the zucchini, diced lobster meat, butter, parmesan cheese and parsley. Stir vigorously to combine. Season with kosher salt to taste.
To plate, scoop generous portions of risotto into 4 bowls. Halve the reserved pieces of claw meat crosswise to make 4 pieces. Garnish each portion with a piece of lobster claw and tail.