seatd: make it a local source package (path=source)

Flip [source] from git=jackpot51/seatd to path="source" so the already-tracked
in-tree source/ (52 files, incl. libseat/seatd-launch) is the authoritative
implementation — a first-class local Red Bear package like evdevd and
redbear-compositor, per Local Fork Supremacy and the operator decision
(INPUT-STACK-LINUX-ALIGNMENT-PLAN.md §4b). We own it and integrate upstream
into our tree rather than fetch+patch.

Does not affect redbear-mini/bare (they do not pull seatd). Making it compile
for Redox + wiring the compositor seat path remain part of the Mesa-gated
desktop bring-up.

local/recipes/system/seatd/recipe.toml

@@ -2,10 +2,18 @@
 name = "seatd"
 version = "0.1.0"
 
-#TODO not compiled or tested
+# seatd is a first-class local Red Bear source package (operator decision): the
+# in-tree `source/` tree is the authoritative implementation, like sibling
+# packages evdevd and redbear-compositor. We own it and integrate upstream
+# (jackpot51/seatd, near-dormant) INTO this tree on our terms, rather than
+# fetching upstream + carrying a patch. See
+# local/docs/INPUT-STACK-LINUX-ALIGNMENT-PLAN.md §4b.
+#
+# TODO(desktop bring-up): still needs a Redox port to compile (meson/C); tracked
+# with the Wayland/compositor seat wiring, which is gated on the Mesa EGL/DRI
+# desktop bring-up. Not pulled by redbear-mini/bare.
 [source]
-git = "https://github.com/jackpot51/seatd"
-branch = "redox"
+path = "source"
 
 [build]
 template = "meson"