Band Lineup 1.13.0: a photo per instrument, picked by the spot each person is in that week

DJ plays drums one week and sings the next; one photo can't fit both. A
person can now have a photo per instrument, named "Name - Instrument"
("DJ - Drums.jpg", "DJ - Vocals.jpg"), plus a plain "DJ.jpg" for
everything else. Sync reads the instrument family of the spot each person
lands in (its bracketed role, else their PCO position) and picks:

1. the photo picked by hand for them on that instrument;
2. a photo named for that instrument;
3. their everyday pick, else their best-named photo. A photo of them on
   another instrument still beats PCO's headshot.

Families keep the shorthands together: Vox/Vocals/Singer, Keys/Piano/Pad,
Drums/Perc, Bass, Guitar/Electric/Acoustic/Rhythm, Leader. A photo
dropped onto someone is remembered per person per instrument
("<id>|drums"), so a drum pick never overrides the vocal photo. A spot
naming several roles files under its most specific: Leader, then Vocals,
Drums, Keys, Bass, Guitar. Photo names from files now collapse the spaces
left by "Name - Instrument".

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

README.md

@@ -525,17 +525,22 @@ below. Nothing is installed without someone clicking.
   name search) scrolling below — drag a photo onto a slot (mouse, or press and
   hold on a touchscreen), drag between slots to swap, rename or clear.
   Dropping a photo onto the person already in a spot makes it *their* photo
-  (a nickname like "Rose" for Rosaliz counts): they keep their Planning Center
-  name and spot, and every later Sync uses that photo for them.
+  for that instrument (a nickname like "Rose" for Rosaliz counts): they keep
+  their Planning Center name and spot, and every later Sync uses it whenever
+  they are on that instrument.
   Planning Center is optional auto-fill on top, not the source of truth:
   **Sync** reads the upcoming plan's team members and places each one. A
   person whose Planning Center note names their mic ("Mix 8, VOX 5") goes to
   that slot — this is how the leader and vocalists, whose position is just
   "Vocalist", land on the right mic — and everyone else goes to the slot
   matching their position, one slot per person. Photos come from the library
-  whenever it has one of them — their remembered pick, else the best name
-  match, even when several photos fit — and Planning Center's headshot only
-  when it has none. Anything placed or moved by
+  whenever it has one of them, and Planning Center's headshot only when it
+  has none. Someone who plays more than one thing can have a photo per
+  instrument, named `Name - Instrument` (`DJ - Drums.jpg`, `DJ - Vocals.jpg`;
+  Vox/Vocals, Keys/Piano, Drums, Bass, Guitar/Electric/Acoustic, Leader), and
+  a plain `DJ.jpg` for everything else: Sync uses the one for the spot they
+  are in that week. A photo dropped onto someone is remembered for that
+  instrument only. Anything placed or moved by
   hand for that plan stays put through later syncs; last week's people are
   replaced.
   Birthdays in the service week (Wednesday→Tuesday) bring a gold glow and