ci(client): lint:pairs keeps a desktop view and its phone twin on one hook

Most features have a desktop view and a phone view, and until now each
carried its own copy of the feature's logic, so a fix on one side drifted
away from the other. With the logic moved into one shared hook per
feature, scripts/feature-pairs.json names every feature with its hooks
and the desktop and phone files that run on them.

lint:pairs fails when a listed view stops importing one of its pair's
hooks (a type only import does not count), when a listed file is gone,
when a hook sits in a view layer rather than under components, hooks,
utils or the folder of a page under pages/, and when a file under
src/mobile/screens is in no pair and not under mobileOnly with the
reason it has no twin. A new phone screen is so either wired to the
desktop feature's hook or marked as phone only on purpose. lint:dup
catches the copies that look alike; this one catches the copies written
anew.

The manifest starts with 120 features and 62 phone only screen files,
each with the reason it stays on the phone alone.

client/CLAUDE.md says how to change a feature, add one with both views
and add a phone screen.

.github/workflows/test.yml

@@ -356,6 +356,14 @@ jobs:
         # its phone twin share stays in one hook (scripts/dup-lint.mjs).
         run: cd client && npm run lint:dup
 
+      - name: Desktop and phone pairs check
+        # Each view in scripts/feature-pairs.json imports its feature's shared
+        # hook, and every file under src/mobile/screens is listed there, as a
+        # view of a pair or as phone only with a reason, so a new phone screen
+        # cannot grow its own copy of a desktop feature's logic
+        # (scripts/pairs-lint.mjs).
+        run: cd client && npm run lint:pairs
+
       - name: Skipped and focused tests check
         run: cd client && npm run lint:skips