build: stages in the plan's own words

`stages_text` on a need gives each stage plain words in the plan's
language. The fallback mails, the road line and the desk buttons use
them, and needs.yaml carries them as `stage_words` so the desk score
describes an outcome the way the site would. The vel's plan has them;
its desks score 26 of 26 where the id-based outcome scored 24.

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

src/plan.rs

@@ -80,6 +80,9 @@ needs:
                               # who hears when a case enters a stage: `submitter` (the form
                               # must then collect a required `email`) or one address. Tell the
                               # person on arrival and on every decision that is about them.
+    stages_text: { open: <words>, <stage>: <words> }
+                              # each stage in the intake's language, where the ASCII id
+                              # would read wrong to a person: "ikke_lost" is "ikke løst"
     events: { open: applied } # ONLY when rebuilding a live site: the event names its
                               # aggregates.yaml already has, so its records keep replaying
     attended_by: >            # ONLY for a stage no desk button moves: the automation that does