chore(cleanup): drop TEMP cursor probes + clear KWin-leg clippy debt

The KWin/Phase-A/B commits were built but never clippy-checked (that distrobox
had no clippy component), so they left TEMP on-glass probes and lint debt in the
tree. With clippy now runnable (fedora rust 1.96.1 = CI parity):

- drop the `fec424ee`/`8cff30d5` TEMP probes: the `update_cursor_meta` SPA_META
  diagnostic logs (also un-detaches the `// SAFETY:` comment from its `unsafe`
  block → fixes `undocumented_unsafe_blocks`) and the KWin composite-arm probe in
  the encode loop.
- `#[allow(clippy::too_many_arguments)]` on `spawn_pipewire` (8 params since the
  KWin leg added `expect_exact_dims`; mirrors `from_virtual_output`).

clippy `-p pf-capture -p pf-vdisplay -p punktfunk-host --locked --features
nvenc,vulkan-encode -- -D warnings` is now green. (--all-targets additionally
trips a pre-existing env mismatch: the fedora libspa binding lacks
`SPA_VIDEO_TRANSFER_SMPTE2084`, referenced only by a `#[cfg(test)]` guard-test —
not a code issue; CI's pinned pipewire has it.)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

include/punktfunk_core.h

@@ -536,7 +536,8 @@
 // whose capture carries no cursor, and NOT Windows yet, where DWM composites into the IDD
 // frame). Set only when the client asked via [`CLIENT_CAP_CURSOR`]; when both bits agree the
 // host stops blending and ships [`CursorShape`](super::control::CursorShape) +
-// [`CursorState`](super::datagram::CursorState) instead. `0x08` — 0x04 is HOST_CAP_TEXT_INPUT.
+// [`CursorState`](super::datagram::CursorState) instead. `0x08` — `0x04` is
+// [`HOST_CAP_TEXT_INPUT`], `0x01`/`0x02` are gamepad-state / clipboard.
 #define HOST_CAP_CURSOR 8
 #endif