listing: syntax-highlight assembly from IDA's own token tags

The listing showed the mnemonic bright and every operand in one body colour.
IDA already classifies each token, for every processor it supports:
generate_disasm_line() emits \x01<tag>text\x02<tag> and the tag says what the
text IS. We were calling tag_remove() and throwing that away.

So: no lexer. A pygments asm lexer would be a worse guess and would need one
dialect per architecture — this is arch-correct for free, including the ARM/MIPS
blobs the loader work just made openable.

  lea rcx, function; "usage"
  insn  reg punct   name   cmt

_idatui_spans() parses the tags into [[kind, text], ...], heads rows carry
"spans", Head.spans holds them, and _span_segments() renders them with a
fallback to the old mnemonic/rest split for older workers.

Palette rule: NEUTRALS for the machine (mnemonic brightest — it's the column you
scan; registers at body weight because they're most of the text), HUES only where
they mean something (numbers, strings, symbols), structure recedes so commas and
brackets stop competing with operands.

Two things that fail SILENTLY and are now encoded:
* The constants are SCOLOR_DATNAME / SCOLOR_CODNAME. There is no SCOLOR_DNAME —
  a wrong guess leaves the tag unmapped, symbols render as plain body text, and
  nothing tells you why. Probed the live IDA to get the real names.
* Spans must be whitespace-collapsed exactly as `text` is, walking characters
  rather than per span, because a run of IDA's column padding straddles span
  boundaries. A row only gets spans when they reconstruct `text` exactly, so a
  mismatch degrades to the old rendering instead of corrupting the line.

The reason this was parked yesterday was NOT a bug in it. listing_view's
"undefining a data head yields an unknown run" waits for
`index_of_ea(dea) >= 0` — but dea is the head it just undefined, so it is in the
OLD model too and the predicate passes instantly, asserting against pre-edit
rows. It only ever passed because the model swap won the race; spans made pages
3x bigger, the swap lost, and the check accused working code. It now waits for
the model to be REPLACED.

Cost measured on libcrypto: 95KB per 500-row page, 50ms; model ensure(2000)
228ms. Acceptable for what it buys.

tests: new asm_highlight scenario (+7) — >90% of code rows carry spans, insn/reg/
punct present, every span kind has a style, spans reconstruct the row text
exactly, mnemonic is the first span. 202/0 scenarios, 26/0 blob, 30/0 project UI.

TODO: DisasmView appears to be dead code (never instantiated; Ctx.dis returns
ListingView), which is why this only needed doing once.

2 files changed, 45 insertions, 9 deletions

diff --git a/idatui/app.py b/idatui/app.py
index dd7c222..6506016 100644
--- a/idatui/app.py
+++ b/idatui/app.py
@@ -53,6 +53,23 @@ from .domain import DisasmModel, Func, Head, ListingModel, Program, Struct
 _S_ADDR = Style(color="#6b7684")
 _S_LABEL = Style(color="#7aa2f7", bold=True)
 _S_INSN = Style(color="#c3cad3")
+#: IDA's token kinds -> the measured palette. The rule that keeps a dense
+#: disassembly readable: NEUTRALS for the machine (mnemonic brightest because you
+#: scan down that column, registers at body weight because they're most of the
+#: text), HUES only where they mean something (numbers, strings, symbols),
+#: structure recedes so brackets and commas stop competing with operands.
+_S_SPAN = {
+    "insn": Style(color="#e8ecf2"),      # 15.3:1  mnemonic / directive
+    "reg": Style(color="#c3cad3"),       # 11.0:1  registers = body weight
+    "num": Style(color="#d8a657"),       #  8.2:1  immediates, offsets
+    "str": Style(color="#9ece6a"),       #  9.9:1  string literals
+    "name": Style(color="#7aa2f7"),      #  7.2:1  symbols / xref targets
+    "seg": Style(color="#93aee0"),       #  8.1:1  segment names
+    "cmt": Style(color="#7c8b9e", italic=True),   # 5.2:1
+    "punct": Style(color="#626c7a"),     #  3.4:1  brackets, commas, +/-
+    "err": Style(color="#c9762f"),       #         IDA's own error marker
+    "text": Style(color="#c3cad3"),      # 11.0:1  anything unclassified
+}
 _S_MNEM = Style(color="#e8ecf2")
 _S_OPBYTES = Style(color="#5e6875")  # raw opcode bytes column
 _S_DATA = Style(color="#d8a657")
@@ -1077,6 +1094,24 @@ class ListingView(SearchMixin, NavMixin, ColumnCursor, ScrollView, can_focus=Tru
             return " ".join(f"{b:02X}" for b in raw[:_OP_LIMIT]) + "\u2026"
         return " ".join(f"{b:02X}" for b in raw)
 
+    @staticmethod
+    def _span_segments(h: Head, fallback: Style):
+        """Segments for a row's disassembly text.
+
+        Uses IDA's own token classification when the worker supplied it; falls
+        back to the old mnemonic/rest split so an older worker (or a row whose
+        spans didn't match the text) still renders.
+        """
+        if h.spans:
+            return [Segment(t, _S_SPAN.get(k, fallback)) for k, t in h.spans]
+        if h.kind == "code":
+            mnem, _, rest = h.text.partition(" ")
+            segs = [Segment(mnem, _S_MNEM)]
+            if rest:
+                segs.append(Segment(" " + rest, fallback))
+            return segs
+        return [Segment(h.text, fallback)]
+
     def _op_field(self, h: Head) -> str:
         """The padded opcode-bytes column (empty when hidden). Shared format so
         cursor/search offsets line up."""
@@ -1301,17 +1336,11 @@ class ListingView(SearchMixin, NavMixin, ColumnCursor, ScrollView, can_focus=Tru
                 segs.append(Segment(_LST_INDENT, _S_MEMBER))
             if h.name:
                 segs.append(Segment(f"{h.name}  ", _S_LABEL))
-            if h.kind == "code":
-                mnem, _, rest = h.text.partition(" ")
-                segs.append(Segment(mnem, _S_MNEM))
-                if rest:
-                    segs.append(Segment(" " + rest, _S_INSN))
-            elif h.kind == "data":
-                segs.append(Segment(h.text, _S_DATA))
-            elif h.kind == "member":
+            if h.kind == "member":
                 segs.append(Segment(h.text, _S_MEMBER))
             else:
-                segs.append(Segment(h.text, _S_UNK))
+                base = {"code": _S_INSN, "data": _S_DATA}.get(h.kind, _S_UNK)
+                segs.extend(self._span_segments(h, base))
             strip = Strip(segs)
         linked = idx in self._link_rows
         if linked:
diff --git a/idatui/domain.py b/idatui/domain.py
index e4fbec9..606cf42 100644
--- a/idatui/domain.py
+++ b/idatui/domain.py
@@ -100,6 +100,10 @@ class Head:
     text: str
     name: str | None = None
     raw: bytes | None = None  # opcode/item bytes (filled in for code by the model)
+    #: [(kind, text)] from IDA's own colour tags — mnem/reg/num/name/str/punct/…
+    #: None when the worker didn't provide them (older worker, or the spans
+    #: disagreed with the plain text, in which case the text wins).
+    spans: tuple[tuple[str, str], ...] | None = None
 
     @property
     def label(self) -> str | None:  # Line-compatible alias
@@ -107,12 +111,15 @@ class Head:
 
     @classmethod
     def from_raw(cls, d: dict) -> "Head":
+        sp = d.get("spans")
         return cls(
             ea=_as_int(d["ea"]),
             kind=d.get("kind", "unknown"),
             size=int(d.get("size", 0) or 0),
             text=d.get("text", ""),
             name=d.get("name"),
+            spans=(tuple((str(k), str(t)) for k, t in sp)
+                   if isinstance(sp, list) and sp else None),
         )