Add window rules, real config validation, and a Wayland DRM/udev backend

- srd.rule(): match windows by title/class, apply floating/maximized/
  workspace/geometry/decoration actions on creation (crates/core/src/rules.rs)
- srd.validate_config()/srd.debug.*: real range/format checks and
  status/profiling helpers, replacing the always-true stub
- Wayland titlebar text rendering via fontdue, unit-tested without a
  display (crates/wayland/src/decoration.rs)
- Wayland precise keybinding matching, replacing the "any Super-held key"
  heuristic, sharing the keysym table with X11 (moved to
  crates/core/src/keysyms.rs)
- Wayland DRM/udev backend (crates/wayland/src/udev.rs): runs as the real
  compositor on a bare TTY via libseat/libinput/KMS, software rendering
  via Pixman + dumb buffers (no GBM/EGL required)
- srdwm_platform::detect() fix, found via VM testing: a bare TTY with no
  DISPLAY/WAYLAND_DISPLAY now correctly resolves to Wayland instead of an
  X11 backend that can never work there
- XWayland integration groundwork (crates/wayland/src/xwayland.rs): spawn,
  X11Wm, and full XwmHandler event routing into the same WindowManager/
  Space pipeline as native clients. Windows don't render yet - a real
  glamor-vs-software-renderer conflict in XWayland's own fallback path,
  root-caused via WAYLAND_DEBUG tracing and documented in
  docs/IMPLEMENTATION_STATUS.md rather than worked around blind.

All verified live in an isolated QEMU VM: X11 backend shows two
decorated, correctly-tiled xterms with real title text; the DRM/udev
Wayland backend opens the GPU, initializes input, and scans out a
rendered frame via KMS page-flip.

1 files changed, 13 insertions, 1 deletions

diff --git a/crates/wayland/Cargo.toml b/crates/wayland/Cargo.toml
index d407bfb..4602608 100644
--- a/crates/wayland/Cargo.toml
+++ b/crates/wayland/Cargo.toml
@@ -10,8 +10,20 @@ srdwm-core.workspace = true
 srdwm-platform.workspace = true
 log.workspace = true
 thiserror.workspace = true
+fontdue = "0.9"
 
 [dependencies.smithay]
 version = "0.7"
 default-features = false
-features = ["backend_winit", "renderer_gl", "desktop", "wayland_frontend"]
+features = [
+    "backend_winit",
+    "backend_drm",
+    "backend_libinput",
+    "backend_udev",
+    "backend_session_libseat",
+    "renderer_gl",
+    "renderer_pixman",
+    "desktop",
+    "wayland_frontend",
+    "xwayland",
+]