Implement native InputCapture with private EIS receiver transport

Add consent, zones and outside-edge barriers, connection-scoped leases, bounded input queues and keyboard/pointer forwarding. Restore local input on release, locking, topology or keymap changes, receiver loss and emergency escape. Preserve held-key state and distinguish finger stops from absent scroll axes.

Validation: independent review cleared; 5 native InputCapture unit tests; 32 portal tests; official D-Bus contract checks on a private bus; real installed libei receiver interoperability test. Live physical barrier and consent interaction remain to be checked in a desktop session.

Cargo.lock

@@ -4886,6 +4886,18 @@ version = "0.8.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d6f6ff9a378485b298a5286656da665ba74413d36db0979633275d2e708145d4"
 
+[[package]]
+name = "reis"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b967ec6489a42067a20724f11987bb96178ea796873cbe1afd25fb93ee6f85f"
+dependencies = [
+ "calloop 0.14.4",
+ "enumflags2",
+ "log",
+ "rustix 1.1.5",
+]
+
 [[package]]
 name = "renderdoc-sys"
 version = "1.1.0"
@@ -7415,6 +7427,7 @@ checksum = "2fb433233f2df9344722454bc7e96465c9d03bff9d77c248f9e7523fe79585b5"
 name = "xdg-desktop-portal-ferese"
 version = "0.1.0"
 dependencies = [
+ "calloop 0.14.4",
  "dirs",
  "ferese-config",
  "ferese-ipc",
@@ -7429,6 +7442,7 @@ dependencies = [
  "memmap2 0.9.11",
  "pipewire",
  "png 0.18.1",
+ "reis",
  "serde",
  "serde_json",
  "tempfile",