Simplify the insufficient-space copy per review

Keep the user-facing message simple; the remedy lives in the self-hosting
docs where the operator can act on it.

Author: jeremy

app/views/account/imports/show.html.erb

@@ -23,7 +23,7 @@
       <% elsif @import.failed_due_to_invalid_export? %>
         <div>The .zip file you uploaded doesn’t look like a Fizzy account export.</div>
       <% elsif @import.failed_due_to_insufficient_space? %>
-        <div>There wasn’t enough space to process your import. Free up at least twice the export file’s size and try again.</div>
+        <div>There wasn’t enough storage space to process your import.</div>
       <% else %>
         <div>This may be due to corrupted export data or a conflict with existing data. Please try again with a fresh export.</div>
       <% end %>

app/views/mailers/import_mailer/failed.html.erb

@@ -5,7 +5,7 @@
 <% elsif @import.failed_due_to_invalid_export? %>
   <p>The ZIP file isn't a Fizzy account export.</p>
 <% elsif @import.failed_due_to_insufficient_space? %>
-  <p>There wasn't enough space to process your import. Free up at least twice the export file's size and try again.</p>
+  <p>There wasn't enough storage space to process your import.</p>
 <% else %>
   <p>This may be due to corrupted export data or a conflict with existing data. Please try again with a fresh export, or reach out for help if the problem persists.</p>
 <% end %>

app/views/mailers/import_mailer/failed.text.erb

@@ -5,7 +5,7 @@ It looks like the account you are trying to import already exists.
 <% elsif @import.failed_due_to_invalid_export? -%>
 The ZIP file isn't a Fizzy account export.
 <% elsif @import.failed_due_to_insufficient_space? -%>
-There wasn't enough space to process your import. Free up at least twice the export file's size and try again.
+There wasn't enough storage space to process your import.
 <% else -%>
 This may be due to corrupted export data or a conflict with existing data. Please try again with a fresh export, or reach out for help if the problem persists.
 <% end -%>

docs/docker-deployment.md

@@ -157,7 +157,7 @@ If you do want to allow multiple accounts to be created in your instance, set `M
 
 You can move an account between Fizzy instances by exporting it on the old instance and uploading the export zip to the new one during signup.
 
-Imports need free space: at least twice the export file's size, beyond the export itself, since the imported attachments roughly mirror the zip's contents. If there isn't enough, the import fails fast with "There wasn't enough space to process your import." — free up space (or grow the volume) and try again. If free space can't be determined, the check is skipped and the import proceeds.
+Imports need free space: at least twice the export file's size, beyond the export itself, since the imported attachments roughly mirror the zip's contents. If there isn't enough, the import fails fast with "There wasn't enough storage space to process your import." — free up space (or grow the volume) and try again. If free space can't be determined, the check is skipped and the import proceeds.
 
 For very large exports:
 

test/mailers/import_mailer_test.rb

@@ -56,6 +56,6 @@ class ImportMailerTest < ActionMailer::TestCase
       email.deliver_now
     end
 
-    assert_match "twice the export file", email.body.encoded
+    assert_match "enough storage space", email.body.encoded
   end
 end