initial seed: retrofit campaign lineage from local working trees

panvk-bifrost campaigns (r1..r4 Vulkan compositor + r5.video1 Vulkan
video decode) shipped before this repo existed; the deliverable
patches live in marfrit-packages, but the reasoning chain, phase docs,
and source-state evidence lived only in local working trees on the
development host.

This retrofit imports:
- mesa-panvk-bifrost/   — r1..r4 era phase docs (iter1..iter18)
                          (libmali stub blobs at iter18/blob/ excluded
                          — 109MB of RE artifacts replaced with a README
                          pointer)
- mesa-panvk-bifrost-video/ — sibling campaign phase docs + probe
- evidence/             — frozen .tgz source snapshots at each milestone
                          (basis for the 0005 patch diff generation)

Future iterations should branch off here from day one, so each iter is
a commit rather than a snapshot. See [[feedback-session-local-process-pins]]
for the process drift this retrofit closes.

Total: 1.9 MB across 124 files.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

mesa-panvk-bifrost/iter13/probe_xfb.vert

@@ -0,0 +1,24 @@
+#version 450
+
+// iter13 XFB probe vertex shader.
+// Writes a known pattern per vertex into transform feedback buffer 0.
+// Each vertex emits one vec4: (vertex_id, instance_id, 0x1234, 0xcafe).
+// With a 3-vertex single-instance draw + buffer offset 0,
+// expected capture (LE float32 array of vec4s):
+//   vertex 0: 0.0, 0.0, 4660.0, 51966.0
+//   vertex 1: 1.0, 0.0, 4660.0, 51966.0
+//   vertex 2: 2.0, 0.0, 4660.0, 51966.0
+
+layout(xfb_buffer = 0, xfb_offset = 0, xfb_stride = 16, location = 0) out vec4 captured;
+
+void main() {
+    // Position is unused (rasterizerDiscardEnable=VK_TRUE) but needed for valid pipeline.
+    gl_Position = vec4(0, 0, 0, 1);
+
+    captured = vec4(
+        float(gl_VertexIndex),
+        float(gl_InstanceIndex),
+        float(0x1234),
+        float(0xcafe)
+    );
+}