disasm: render opcode bytes (toggle 'o'), padded to widest insn

Fetch per-instruction opcode bytes alongside the disasm listing and show
them in a column between the address and the mnemonic. Instruction length
comes from consecutive addresses (variable-length safe: x86 movabs shows
its full 10 bytes); the block over-fetches one instruction for the last
line's boundary, falling back to the function end for the final insn.

The column pads to the widest instruction across the whole function:
_fetch_block tracks a running max, and on load a background scan_bytes()
settles a stable width so padding doesn't jump as blocks stream in.
_op_field is shared by the rendered strip, _line_plain, and search _fmt
so cursor/match offsets stay aligned. 'o' toggles the column.

1 files changed, 3 insertions, 1 deletions

diff --git a/uv.lock b/uv.lock
index 19d24a7..91414b5 100644
--- a/uv.lock
+++ b/uv.lock
@@ -21,13 +21,15 @@ dev = [
     { name = "pytest" },
 ]
 tui = [
+    { name = "pygments" },
     { name = "textual" },
 ]
 
 [package.metadata]
 requires-dist = [
+    { name = "pygments", marker = "extra == 'tui'", specifier = ">=2" },
     { name = "pytest", marker = "extra == 'dev'", specifier = ">=8" },
-    { name = "textual", marker = "extra == 'tui'", specifier = ">=0.60" },
+    { name = "textual", marker = "extra == 'tui'", specifier = ">=8" },
 ]
 provides-extras = ["tui", "dev"]