build: the lift matches cards by identity, not position

Sequences were walked side by side, so a rebuilt page whose cards sit
in a different order, or with a new card in front, gave every card
its neighbour's words: uhhm.no's front door got "Attention is earned"
on the wrong card that way. Items now match on the bucket they record
into, the page they lead to, a field's name, the group they invite
into or the bucket they read; information features with no identity
still match by position. Lifting live uhhm.no into the current plan
puts each of its three headings on the card with its bucket.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

README.md

@@ -45,9 +45,12 @@ default.
 
 `--words-from <repo>` lifts the words a repo already has back into the
 words map by structure, so a rebuild keeps hand-edited wording and
-adds only the new slots. The lift is by position, so it holds for a
-rebuild of the same shape and not across a restructure: on uhhm.no it
-put the old front door's three headings on three new cards. `--words
+adds only the new slots. Cards are matched by what they are (the
+bucket they record into, the page they lead to, a field's name, the
+group they invite into), not by position, so a rebuild that reorders
+or reshapes a page still hands each card its own words; on uhhm.no
+the live front door's three headings follow their buckets onto the
+new page. `--words
 <json>` overrides slots by page and may repeat, each file layered over
 the last (the words a build used, then a round of hand changes);
 `words.json` in the output is the words as used. See