Import lists from CSV or text and match each entry

The list editor gets an Import button. A .csv/.tsv/.txt file or pasted
text is parsed on the server: header columns (Title, Year, Artist or
Director, Note, Rank), numbered lines and trailing "(1999)" years are
understood, and Canon's own export round-trips.

Each row is then searched with the list's provider and scored. A row is
matched automatically only when one result fits exactly and nothing else
fits as well; a year or artist in the file breaks ties, an exact title
beats a bracketed version like "(Live)", and "Artist - Title" lines are
tried both ways. Custom lists need a year or subtitle to be certain.
Everything else is shown for review with a recommended pick, the other
results, "Add as written", Skip, and a search-again box. Entries are
added in file order after the existing ones, with any notes from the
file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -129,6 +129,15 @@ A list can hold 1 to 65,535 entries. The editor recommends **100 or fewer** and
 
 To share with friends and family without being fully public, set a password under **Settings → Privacy → Site password**. Visitors then see a password prompt over a blurred placeholder; none of your lists, images or profile are sent until they enter it. Once they do, that browser stays unlocked for 90 days. Changing the password asks everyone for the new one, and you never need it while signed in. A protected site also tells search engines not to index it.
 
+## Importing a list
+
+**Import** in the list editor adds entries from a file, after the ones already there and in the file's order:
+
+- **Text** (`.txt`, or paste): one title per line. Numbering like `1.` is dropped when every line has it, and a trailing `(1999)` is read as the year. For songs and albums, `Artist - Title` works either way round.
+- **CSV / TSV**: a header row picks the columns: `Title` (or Name), `Year`, `Artist`/`Director`/`Developer`, `Note` (or Why), and `Rank` to set the order. Without a header the first column is the title. Canon's own export imports as-is.
+
+Each entry is searched for and matched. Canon only adds a match on its own when it's certain: the title matches exactly and nothing else fits as well (a year or artist in the file helps). Everything else is left for you to check, with a recommended pick, the other results, **Add as written** to make a new entry from your text, **Skip**, and a box to search again. Custom lists search all of Wikipedia, so there a match is only certain when a year or subtitle confirms it.
+
 ## Exporting a list
 
 Every list can be downloaded as its titles only, in rank order, one per line. There are no ranks, header row or other fields.