feat: add manual disk discovery and weekly capacity cache

tests/test_storage_cache.py

@@ -6,7 +6,7 @@ from storage_cache import StorageCache
 
 
 class StorageTests(unittest.TestCase):
-    def test_daily_reads_and_restart_cache(self):
+    def test_weekly_reads_and_restart_cache(self):
         with tempfile.TemporaryDirectory() as directory:
             now=[1000];reads=[]
             def reader(path):
@@ -18,7 +18,7 @@ class StorageTests(unittest.TestCase):
             self.assertEqual(len(reads),1)
             restored=StorageCache(p,reader,lambda:now[0]);restored.sample()
             self.assertEqual(len(reads),1)
-            now[0]=87400;restored.sample()
+            now[0]=605800;restored.sample()
             self.assertEqual(len(reads),2)
 
     def test_failure_does_not_fabricate_zero_or_retry_each_second(self):