feat(diag): aggregating + filtered trace sinks (histogram, op-filter, per-script)

The existing trace framework only had a flat text formatter, so every question
became 'dump millions of lines, then grep'. This session that cost a long wrong
detour. Add, all observe-only (parity preserved):

- HistogramTraceSink: execution counts per opcode AND per call-site (script:pc)
  with a sample operand. Dumped sorted after the run. This is what instantly
  showed the 493k headless 'sleep's are INPUTNAME.BIN:0x1c3 (a name-entry poll
  loop), not the opening.
- TraceSinkBase: tracks the frame stack -> attributes each step to its REAL
  script (nested call-script frames included) = the 'which script is this pc in?'
  answer a bare step trace can't give.
- TextTraceSink: op-filter (--trace-ops sleep,draw-texture,...) + script:pc tags.
- CompositeTraceSink: fan-out (text + histogram + Godot's call-script queue).
- OpcodeTable.ByLabel: mnemonic -> opcode for --trace-ops.
- CLI: --trace-histogram, --trace-ops, robust --trace-file (mkdir -p).
- Godot: --trace-histogram <file> profiles the REAL run (headless flow diverges:
  real run to page 1 is 562 steps / 0 sleeps vs headless 2M steps / 493k sleeps).
- Also: --sleep-scale <f> debug knob to slow the paced opening for inspection.

Engine 56/56 (4 new); sweep parity 284/13; Godot builds + dogfooded end-to-end.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

godot/GodotAdvHost.cs

@@ -47,9 +47,10 @@ public sealed class GodotAdvHost : IHost
     // Time-based sibling of WaitForInput's suspend. The native op arms a non-blocking main-loop-polled timer;
     // blocking this throwaway task thread is behaviorally equivalent given our threading model. Operand is
     // MILLISECONDS (docs/engine-re.md sleep section + opcodes.toml 0xc8). Headless CLI hosts no-op it (parity).
+    public double SleepScale = 1.0;   // --sleep-scale <f>: debug multiplier to slow/speed the paced opening for inspection
     public void Sleep(long duration)
     {
-        int ms = (int)System.Math.Clamp(duration, 0, 10_000);   // cap so a pathological script can't hang the window
+        int ms = (int)System.Math.Clamp(duration * SleepScale, 0, 60_000);   // cap so a pathological script can't hang the window
         if (ms > 0) Thread.Sleep(ms);
     }