Limit length of numerical habit units to 7

uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/edit/EditHabitActivity.kt

@@ -314,6 +314,10 @@ class EditHabitActivity : AppCompatActivity() {
                 binding.targetInput.error = getString(R.string.validation_cannot_be_blank)
                 isValid = false
             }
+            if (binding.unitInput.text.length > resources.getInteger(R.integer.unit_name_max_length)) {
+                binding.unitInput.error = getString(R.string.validation_unit_too_long)
+                isValid = false
+            }
         }
         return isValid
     }

uhabits-android/src/main/res/layout/activity_edit_habit.xml

@@ -167,6 +167,7 @@
                         android:id="@+id/unitInput"
                         android:maxLines="1"
                         android:ems="10"
+                        android:maxLength="@integer/unit_name_max_length"
                         android:hint="@string/measurable_units_example"/>
                 </LinearLayout>
             </FrameLayout>

uhabits-android/src/main/res/values/constants.xml

@@ -28,6 +28,9 @@
     <string name="bugReportTo">dev@loophabits.org</string>
     <string name="bugReportSubject">Bug Report - Loop Habit Tracker</string>
     <string name="syncBaseURL" formatted="false">https://sync.loophabits.org</string>
+    
+    <!-- Maximum length for unit names in numerical habits -->
+    <integer name="unit_name_max_length">7</integer>
 
     <string-array name="snooze_picker_names">
         <item>@string/interval_15_minutes</item>

uhabits-android/src/main/res/values/strings.xml

@@ -235,4 +235,5 @@
     <string name="pref_midnight_delay_description">Wait until 3:00 AM to show a new day. Useful if you typically go to sleep after midnight. Requires app restart.</string>
     <string name="pref_animations_title">Disable animations</string>
     <string name="pref_animations_description">Disable confetti animation after adding a checkmark.</string>
+    <string name="validation_unit_too_long">Unit name is too long.</string>
 </resources>