citizen: add foundry build config

foundry.toml

@@ -0,0 +1,33 @@
+[profile.default]
+src = "contracts"
+test = "test"
+script = "script"
+out = "out"
+libs = ["lib"]
+solc_version = "0.8.24"
+optimizer = true
+optimizer_runs = 200
+via_ir = false
+
+[profile.default.fuzz]
+runs = 256
+max_test_rejects = 65536
+
+[profile.ci]
+fuzz = { runs = 1024 }
+verbosity = 3
+
+[fmt]
+line_length = 120
+tab_width = 4
+bracket_spacing = false
+int_types = "long"
+multiline_func_header = "attributes_first"
+quote_style = "double"
+number_underscore = "thousands"
+single_line_statement_blocks = "single"
+
+[doc]
+out = "docs"
+
+# See: https://book.getfoundry.sh/reference/config/