Add RDNA4 (gfx12) support and a 0.1.2 optimization round

RDNA4 (experimental; untested on RDNA4 hardware)
- kernels/common/wmma_layout.h picks the WMMA operand/accumulator layout
  per target; K (pwin_*) and M (swin_*) index through it, so the same
  sources build for gfx11 and gfx12. D4R_WMMA_LAYOUT=12 on gfx11 is a test
  shim that runs the gfx12 indexing on gfx11 WMMA.

- M can use native e4m3 FP8 WMMA on gfx12 (D4R_NATIVE_FP8=1). Texture
  tails (enc0_tail, dec0_head) get gfx12 f16 and FP8 paths that match
  ZLUDA's gfx12 lowering.

- ZLUDA patch 0007: gfx12 WMMA helpers, optional native FP8 MMA
  (D4R_ZLUDA_WMMA_FP8_NATIVE), a layout override for testing, and an
  architecture argument for d4r_emit. Texture kernels are now compiled
  offline per target through d4r_emit (D4R_ZLUDA_EMIT) instead of on the
  local GPU.

- New d4r.ini option [Kernels] NativeFp8 (default on), wired through the
  shim and d4r_config.py. On gfx12 the bridge serves kernels/<arch>-fp8
  when it is on.

- The bridge picks the KFD GPU with the most SIMDs (so an iGPU is not
  chosen over a discrete GPU); D4R_GPU_ARCH overrides it.

- kernels/build.sh and package_release.sh build gfx1100-gfx1103 and
  gfx1200/gfx1201 (plus -fp8 variants), and D4R_BUNDLE_TEX takes
  per-target folders.

Performance (RDNA3; harness byte-identical unless noted)
- ZLUDA patch 0006: m16n8k8 f16 MMAs on WMMA (E; not bit-exact, 52-55 dB
  per layer, D4R_ZLUDA_WMMA_K8=0 disables it), per-key weight-image slots
  for native prep kernels (d4r_prep_key_at, d4r_prep_key_slots), and
  wave64 builds of MMA-free kernels (D4R_ZLUDA_WAVE64).

- M: packed FP8 encoding, conflict-free patch-merge reads, scalar weight
  loads in enc1, and weight prep once per weight set for the six enc3
  tube blocks.

- K: CU mode for the six non-wide pwin layers.

- Texture kernels: every DLSS flag variant is built natively (24 K output,
  8 M post, 4 M downsample, 4 M enc0), not only Townfall's; post and K
  output run as wave64.

- M direct output: rrlite_downsample_kernel writes the shim's output
  buffer; the shim's default direct-output presets are now 11,13.

Tools
- dump_runner takes the prep grid from d4r_prep_blocks and refuses
  texture/surface dumps.

- New pwin_check.py, swin_check.py, model_enc3.py and tail_check.hip.

Docs: README GPU table and RDNA4 notes, building (patches 0002-0007,
d4r_emit), native-kernels (RDNA4 section), performance (new numbers),
packaging README. Version 0.1.2.

docs/performance.md

@@ -1,5 +1,7 @@
 # Performance
 
+All frame rates and kernel timings on this page were measured on an RX 7700 XT (gfx1101). RDNA4 (gfx1200/gfx1201) has compile and emulator validation only; no RDNA4 frame rate, latency, or kernel timing has been measured. Native FP8 may change both arithmetic and cost, so the gfx11 results cannot be projected to it.
+
 ## Method
 
 - **Hardware and settings:** Radeon RX 7700 XT (RDNA3, 54 CUs), Ryzen 9 5900XT, Linux 6.18. SILENT HILL Townfall at 2560×1440 output.
@@ -8,18 +10,20 @@
 - **Pairing:** runs are compared back-to-back in one session, because repeated runs of an identical setup vary by about 1%.
 - **Screen recording:** it costs a few fps, so recorded videos show slightly lower numbers than the table.
 - **Latency:** all DLSS numbers are same-frame (frame age 0). Every frame shows its own DLSS result, as with a native upscaler.
-- **Other upscaler modes:** Balanced, Performance and Ultra Performance use OptiScaler's render-ratio override (1.72, 2.0, 3.0) on top of the game's Quality mode.
+- **Upscaler modes:** every mode uses OptiScaler's render-ratio override (1.5, 1.72, 2.0, 3.0), so the result does not depend on the DLSS mode chosen in the game.
 
 ## Results
 
-| Mode (render resolution) | DLSS 3 CNN (E) | DLSS 4 (K) | DLSS 4.5 (M) | FSR 4 |
+| Mode (render resolution) | DLSS 3 CNN (E) | DLSS 4 (K) | DLSS 4.5 (M) | FSR 4\* |
 |---|---|---|---|---|
-| Quality (1705×960) | **72.4** | 69.4 | 51.5 | 76.0 |
-| Balanced (1488×837) | **80.5** | 76.6 | 59.6 | 84.5 |
-| Performance (1280×720) | **87.8** | 84.0 | 69.9 | 94.0 |
-| Ultra Performance (853×480) | 88.9 | **94.5** | 90.3 | 107.3 |
+| Quality (1705×960) | **71.7** | 67.9 | 49.3 | 76.0 |
+| Balanced (1488×837) | **80.8** | 75.9 | 58.0 | 84.5 |
+| Performance (1280×720) | **89.7** | 84.1 | 69.0 | 94.0 |
+| Ultra Performance (853×480) | 89.1 | **95.5** | 92.2 | 107.3 |
 | Native 2560×1440, no upscaling (TSR at 100%) | | 49.1 | | |
 
+\* FSR 4 and the native row are from 2026-09-27; the DLSS columns from 2026-09-29, when the machine ran about 2–4% slower overall (release 0.1.1 at Quality that day: E 71.2, K 67.9, M 48.4 fps, against 72.4, 69.4 and 51.5 two days earlier). The render resolution of every mode is set with OptiScaler's ratio override for whichever DLSS mode the game is set to (ratios 1.5, 1.72, 2.0 and 3.0).
+
 DLSS 4's cost is almost constant across modes (about 2.8 ms of GPU time per frame). Its network runs on a grid set by the output resolution, not the render resolution, so the gap to FSR 4 widens as the render resolution drops. The CNN gets more expensive at the 3× ratio, so K is the better choice at Ultra Performance.
 
 ## What each step contributed