PC port: phase 2 — D48 review: re-plan D43 as offline pre-conversion (Plan B)

- D48 finding in PCPortResearch.md §F: d43_convert.py does not emit bytes
  (layout+remap validation only); Plan B = Python emit pass -> data/pcmodels-<region>/
  RZ sidecars served via port-layer hw_address/rom_size table patch (no C
  converter); Plan A kept as fallback with corrected staging guard (D_N64+D_PC<=avail)
- Moved all 23 d43_*.py investigation scripts from gitignored build-pc/ to tracked
  tools_pc/ (spec is now versioned); d43_cover.py path ref updated; converter
  re-run from new location: ALL CLEAN
- HANDOFF.md rewritten as two-session prompt: Session A = independent review of
  Plan B (8 claims, each with falsification criterion -> finding D49), Session B =
  execute (emit pass + round-trip validator, romdata plumbing, one-line hook,
  pixel-assert soak); verified-facts converter spec preserved
- AGENTS.md phase status updated to D48 re-plan

tools_pc/d43_tree_dump.py

@@ -0,0 +1,48 @@
+import csv, struct, sys, zlib, os, re
+ROM = r"data/ge007.ntsc-final.z64"
+rom = open(ROM, "rb").read()
+rows = list(csv.reader(open(r"scripts/filelist.u.csv")))
+hdrfiles = set()
+for root, dirs, files in os.walk("assets"):
+    for fn in files:
+        if fn.lower().endswith("modelfileheader.inc.c"): hdrfiles.add(os.path.join(root, fn))
+nsnt = {}
+for f in sorted(hdrfiles):
+    for line in open(f):
+        m = re.search(r"MODELFILEHEADER\((.*)\)\s*;?\s*$", line)
+        if not m: continue
+        a = [x.strip() for x in m.group(1).split(",")]
+        if len(a) < 9: continue
+        try: nsnt[a[0]] = (int(a[4], 0), int(a[8], 0))
+        except ValueError: pass
+def be32(b, o): return struct.unpack_from(">I", b, o)[0] & 0xFFFFFF
+flt = sys.argv[1]
+for r in rows:
+    if len(r) < 3 or not r[2]: continue
+    base = r[2].rsplit("/",1)[-1]
+    if base.endswith(".bin"): base = base[:-4]
+    if flt.lower() not in base.lower(): continue
+    key=None
+    for cand in (base, base[1:], base[:-1], base[1:-1]):
+        if cand in nsnt: key=cand; break
+    if not key: continue
+    NS,NT = nsnt[key]
+    addr,size=int(r[0]),int(r[1])
+    out=zlib.decompress(rom[addr:addr+size][2:],-15)
+    D=len(out); R0=4*NS+12*NT
+    print("== %s D=0x%X NS=%d NT=%d R0=0x%X" % (base,D,NS,NT,R0))
+    seen=set()
+    def show(o, depth):
+        if o in seen or o>=D: return
+        seen.add(o)
+        op=struct.unpack_from(">H",out,o)[0]&0xff
+        data=be32(out,o+4); par=be32(out,o+8); nxt=be32(out,o+0xC); prv=be32(out,o+0x10); ch=be32(out,o+0x14)
+        print("  %snode op=%-2d @%05X data=%05X par=%05X next=%05X prev=%05X child=%05X" % (" "*depth, op, o, data, par, nxt, prv, ch))
+        if data < D:
+            # print first 12 words of the record
+            ws=[be32(out,data+4*k) for k in range(min(6,(D-data)//4))]
+            print("      rec: "+ " ".join("%06X"%w for w in ws))
+        if ch: show(ch, depth+1)
+        if nxt: show(nxt, depth+1)
+    show(R0, 0)
+    break