chore: add full MIT text, name the copyright holder properly

LICENSE held only the two-line stub and no LICENSE.md existed, so the
repo carried no license text for a human browsing it or for GitHub's
license detector.

usethis::use_mit_license() writes LICENSE.md but leaves an existing
LICENSE alone, so the stub kept saying 'Civilytics' while the full text
said 'Civilytics Consulting LLC'. Corrected by hand, with a test pinning
the two together.

LICENSE

@@ -1,2 +1,2 @@
 YEAR: 2026
-COPYRIGHT HOLDER: Civilytics
+COPYRIGHT HOLDER: Civilytics Consulting LLC

LICENSE.md

@@ -0,0 +1,21 @@
+# MIT License
+
+Copyright (c) 2026 Civilytics Consulting LLC
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

tests/testthat/test-config.R

@@ -108,3 +108,17 @@ test_that("DESCRIPTION carries release metadata", {
   expect_s3_class(people, "person")
   expect_true("cre" %in% unlist(lapply(people, function(p) p$role)))
 })
+
+test_that("LICENSE and LICENSE.md name the same copyright holder", {
+  skip_if_no_source_tree("LICENSE", "LICENSE.md")
+  holder <- sub("^COPYRIGHT HOLDER:\\s*", "",
+                grep("^COPYRIGHT HOLDER:", readLines(source_tree_path("LICENSE"),
+                                                     warn = FALSE), value = TRUE))
+  full <- paste(readLines(source_tree_path("LICENSE.md"), warn = FALSE), collapse = "\n")
+
+  expect_equal(holder, "Civilytics Consulting LLC")
+  expect_match(full, holder, fixed = TRUE)
+  # usethis::use_mit_license() writes LICENSE.md but leaves an existing
+  # LICENSE alone, which is how the two came to disagree in the first place.
+  expect_match(full, "MIT License", fixed = TRUE)
+})