docs: the droplet spec's refr, ghost and shadow knobs

The key list stopped at `core`, but `DropletSpec::parse` has accepted
three more since the compositor's droplet backdrop pass landed. They are
not all the same kind of knob, so they are documented as two groups
rather than appended to the run: `refr` and `ghost` are read by the
compositor alone — a Wayland client cannot see behind its own surface —
while `shadow` is drawn here, by the same shader mode 10 that draws the
drop.

That last one also corrects the sentence it sits in. The drop box was
described as inset 1px from the surface bottom for the silhouette's AA
feather; it is inset by that plus `shadow_gap()`, the room the contact
shadow falls off into, at all three call sites.

Co-Authored-By: Claude Opus 5 <[email protected]>

 CLAUDE.md | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/CLAUDE.md b/CLAUDE.md
index aa054b3..f487318 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -145,12 +145,20 @@ background_blur tint scaling still applies on top) and `module { text_color }`
 style — cce-ui's `Prim::Droplet`, shader mode 10; the key's PRESENCE enables
 it, its value is whitespace-separated `k=v` pairs onto `DropletSpec` — sag,
 belly, belly_w, blend, sheet_r, attach, clarity, dome, band, gleam, shine,
-rim, bow, curve, core; defaults = the oval dewdrop (no belly; attach 0.42 +
-sheet_r 0.58 fill the height so there is NO straight side; bow arcs the
-bottom; curve 2.6 = superellipse joins, so everything but the flat top is one
-continuous curve), belly>0 brings back the pendant-pool look —
-warn-and-skip on unknown keys; the expanded menu box becomes the drop growing,
-and drops inset 1px from the surface bottom for the silhouette's AA feather)
+rim, bow, curve, core, refr, ghost, shadow; defaults = the oval dewdrop (no
+belly; attach 0.42 + sheet_r 0.58 fill the height so there is NO straight
+side; bow arcs the bottom; curve 2.6 = superellipse joins, so everything but
+the flat top is one continuous curve), belly>0 brings back the pendant-pool
+look — warn-and-skip on unknown keys. Three of those knobs are not this
+side's: `refr` (rim refraction, logical px) and `ghost` (the inverted lens
+image in the belly) are read by the COMPOSITOR, whose scenefx droplet node
+bends the backdrop behind the drop — a Wayland client cannot see behind its
+own surface, so this side parses them and draws nothing. `shadow` (0-1, the
+contact shadow under the drop's lower arc) IS drawn here, and it is why the
+drop box does not fill the surface: the box is inset by 1px for the
+silhouette's AA feather plus `DropletSpec::shadow_gap()` for the shadow's
+falloff (`main.rs`, three call sites — left, right, and the expanded menu
+box, which becomes the drop growing))
 and `module { text_raise }` (lifts module text above vertical center, logical
 px, bar-side only — every module funnels through `centered_text_y`) and
 `module { text_scrim }` (0-1 resting opacity of a