Scrub spinner glyphs from window-title bucket keys

Bucket keys are {Class, ScrubTitle(Title)}, so each animated progress frame a
terminal app cycles into its title (Claude Code's braille and dingbat-star
glyphs) became a distinct bucket — fragmenting one task into dozens of rows and
inflating the switch count, since applyEvent counts a switch per key change.

ScrubTitle now drops any non-ASCII symbol or control rune and collapses leftover
whitespace. This is category-based rather than range-based, so future spinner
sets are covered too, while letters and digits of every script survive and ASCII
symbols (e.g. "C++") are left intact.

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

internal/evidence/evidence.go

@@ -6,6 +6,8 @@ package evidence
 import (
 	"context"
 	"regexp"
+	"strings"
+	"unicode"
 )
 
 // EvidenceHealth records whether the sensor could observe the active window.
@@ -32,8 +34,24 @@ type Source interface {
 // keys (e.g. "1:23", "50.5%", "-3.0"). Ported verbatim from the Rust impl.
 var titleNoise = regexp.MustCompile(`-?\d+([:.]\d+)+%?`)
 
-// ScrubTitle removes volatile numeric runs so window titles bucket stably.
-// The raw event log keeps the unscrubbed title; only bucket keys are scrubbed.
+// extraSpace collapses the whitespace runs left behind by the scrubs below.
+var extraSpace = regexp.MustCompile(`\s+`)
+
+// ScrubTitle normalizes a window title into a stable bucket key. It drops
+// volatile numeric runs (clocks, ratios, percentages) and any non-ASCII symbol
+// or control rune. The latter covers the animated spinner frames terminal apps
+// (e.g. Claude Code) cycle through their title — braille and dingbat glyphs are
+// both Unicode symbol category, so a single task no longer fragments into dozens
+// of buckets. Letters and digits of every script survive, as do ASCII symbols
+// (so "C++" is not mangled). Leftover whitespace is collapsed. The raw event log
+// keeps the unscrubbed title; only bucket keys (and their display) are scrubbed.
 func ScrubTitle(title string) string {
-	return titleNoise.ReplaceAllString(title, "")
+	title = titleNoise.ReplaceAllString(title, "")
+	title = strings.Map(func(r rune) rune {
+		if unicode.IsControl(r) || (r > unicode.MaxASCII && unicode.IsSymbol(r)) {
+			return -1
+		}
+		return r
+	}, title)
+	return strings.TrimSpace(extraSpace.ReplaceAllString(title, " "))
 }