Fix a couple of type issues

src/runboat/db.py

@@ -69,7 +69,7 @@ class BuildsDb:
             return None
         return self._build_from_row(row)
 
-    def remove(self, name: str) -> None:
+    def remove(self, name: str) -> bool:
         if self.get(name) is None:
             return False  # no change
         with self._con:
@@ -77,7 +77,7 @@ class BuildsDb:
         _logger.info("Noticed removal of %s", name)
         return True
 
-    def add(self, build: Build) -> None:
+    def add(self, build: Build) -> bool:
         prev_build = self.get(build.name)
         if prev_build == build:
             return False  # no change

src/runboat/models.py

@@ -48,8 +48,8 @@ class Build(BaseModel):
     def __str__(self) -> str:
         return f"{self.slug} ({self.name})"
 
-    def __eq__(self, other: "Build") -> bool:
-        if other is None:
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, Build):
             return False
         if self.name != other.name:
             return False