Add self-tracing tooling and standardize trace macros

.trace_ignore

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+# Functions to exclude from automatic TRACE_ insertion.
+# One per line. Supports bare names (main) or qualified (Class::method).
+# Blank lines and #comments are ignored.
+
+# SAX parser callbacks — called per JSON token, far too hot to trace
+SaxHandler::key
+SaxHandler::handle_number
+SaxHandler::string
+SaxHandler::args_append
+SaxHandler::start_object
+SaxHandler::end_object
+SaxHandler::escape_json_string
+SaxHandler::finish_event
+
+# Flame graph tree building — called per event during indexing
+FlameGraphPanel::find_or_create_child
+FlameGraphPanel::find_or_create_root
+
+# Called multiple times per frame for every action
+KeyBindings::is_pressed

scripts/find_noisy_traces.py

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+#!/usr/bin/env python3
+"""Find functions called more than a given rate in a Chrome trace JSON file.
+
+Usage:
+    python3 scripts/find_noisy_traces.py <trace.json> [--threshold 200]
+
+Streams the file so it can handle multi-GB traces without loading into memory.
+"""
+
+import argparse
+import ijson
+from collections import Counter
+
+
+def main():
+    p = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    p.add_argument("trace", help="Path to Chrome trace JSON file")
+    p.add_argument("--threshold", type=float, default=200, help="Min calls/second to report (default: 200)")
+    args = p.parse_args()
+
+    counts = Counter()
+    min_ts = float("inf")
+    max_ts = 0
+
+    with open(args.trace, "rb") as f:
+        for event in ijson.items(f, "traceEvents.item"):
+            name = event.get("name", "")
+            ts = event.get("ts", 0)
+            if ts:
+                min_ts = min(min_ts, ts)
+                max_ts = max(max_ts, ts)
+            if name:
+                counts[name] += 1
+
+    duration_s = (max_ts - min_ts) / 1_000_000
+    total = sum(counts.values())
+    min_count = args.threshold * duration_s
+
+    print(f"Trace duration: {duration_s:.1f}s")
+    print(f"Total events: {total}")
+    print(f"Threshold: {args.threshold:.0f}/s (>{int(min_count)} total)")
+    print()
+
+    found = 0
+    for name, count in counts.most_common():
+        rate = count / duration_s
+        if rate < args.threshold:
+            break
+        found += 1
+        print(f"  {rate:8.0f}/s  {count:8d}x  {name}")
+
+    if not found:
+        print("  (none)")
+
+
+if __name__ == "__main__":
+    main()