feat(dialyzer): add typecheck stage to full CI pipelines

.drone.jsonnet

@@ -27,7 +27,7 @@ local step_compute_cache = {
 local step_restore_cache = {
   name: 'restore-cache',
   image: 'drillster/drone-volume-cache',
-  settings: { restore: true, mount: ['./deps', './_build'], ttl: 30 },
+  settings: { restore: true, mount: ['./deps', './_build', './priv/plts'], ttl: 30 },
   volumes: cache_mount,
 };
 
@@ -47,6 +47,20 @@ local step_lint = {
   ],
 };
 
+local step_typecheck = {
+  name: 'typecheck',
+  image: elixir,
+  commands: [
+    'mix local.hex --force',
+    'mix deps.get',
+    'mkdir -p priv/plts',
+    // Build/refresh PLT — no-op on cache hit, full build (5-15 min) on cache miss.
+    'mix dialyzer --plt',
+    // Actual typecheck. --format short keeps log noise down on red builds.
+    'mix dialyzer --format short',
+  ],
+};
+
 local step_wait_postgres = {
   name: 'wait_for_postgres',
   image: postgres_image,
@@ -69,7 +83,7 @@ local step_wait_postgres = {
 local step_rebuild_cache = {
   name: 'rebuild-cache',
   image: 'drillster/drone-volume-cache',
-  settings: { rebuild: true, mount: ['./deps', './_build'] },
+  settings: { rebuild: true, mount: ['./deps', './_build', './priv/plts'] },
   volumes: cache_mount,
 };
 
@@ -99,6 +113,7 @@ local check_pipeline(name, trigger, test) = {
     step_compute_cache,
     step_restore_cache,
     step_lint,
+  ] + (if test.name == 'test-all' then [step_typecheck] else []) + [
     step_wait_postgres,
     test,
     step_rebuild_cache,