Patch headers and comments: concise

Document the patch calling convention once in lib/default.nix; patch
headers say what, target, hook, state and contracts. Comments only, no
code changes.

modules/steam-close-button/unpatch.js

@@ -1,10 +1,7 @@
-// Reverts steam-close-button/patch.js: removes its overrides, reactions and
-// markers (the X disappears). Teardown only: it never switches frames and
-// leaves window.__sfuiSteamCloseState (bar-only flag etc.) in place, so a
-// re-injection (service restart, switch) continues where it left off; if the
-// patch is gone for good while bar-only, the dashboard just stays without an
-// active frame until the next tab click or dashboard open. Safe when not
-// patched.
+// Reverts steam-close-button/patch.js (the X disappears). Never switches
+// frames and keeps window.__sfuiSteamCloseState, so a re-injection continues;
+// if removed while bar-only, the dashboard stays without an active frame
+// until the next tab click or open. Safe when not patched.
 (() => {
   const s = window.__sfuiSteamClose;
   if (!s) return 'not patched';