Port allowed-context matching to evidence package

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

internal/evidence/context.go

@@ -0,0 +1,96 @@
+package evidence
+
+import (
+	"strings"
+
+	"antidrift/internal/domain"
+)
+
+// MatchesAllowed reports whether a window (class/title) is on-task per ctx.
+// M3 matches on window class and title only; the domain and command helpers are
+// ported for completeness and tests but have no live data source yet.
+func MatchesAllowed(ctx domain.AllowedContext, class, title string) bool {
+	return windowClassAllowed(ctx, class) || windowTitleAllowed(ctx, title)
+}
+
+func windowClassAllowed(ctx domain.AllowedContext, candidate string) bool {
+	candidate = normalizeCasefolded(candidate)
+	if candidate == "" {
+		return false
+	}
+	for _, allowed := range ctx.WindowClasses {
+		if normalizeCasefolded(allowed) == candidate {
+			return true
+		}
+	}
+	return false
+}
+
+func windowTitleAllowed(ctx domain.AllowedContext, candidate string) bool {
+	candidate = normalizeCasefolded(candidate)
+	if candidate == "" {
+		return false
+	}
+	for _, allowed := range ctx.WindowTitleSubstrings {
+		a := normalizeCasefolded(allowed)
+		if a != "" && strings.Contains(candidate, a) {
+			return true
+		}
+	}
+	return false
+}
+
+func domainAllowed(ctx domain.AllowedContext, candidate string) bool {
+	candidate = normalizeDomain(candidate)
+	if candidate == "" {
+		return false
+	}
+	for _, allowed := range ctx.Domains {
+		a := normalizeDomain(allowed)
+		if a == "" {
+			continue
+		}
+		if candidate == a {
+			return true
+		}
+		if strings.HasSuffix(candidate, a) && strings.HasSuffix(candidate[:len(candidate)-len(a)], ".") {
+			return true
+		}
+	}
+	return false
+}
+
+func commandAllowed(ctx domain.AllowedContext, candidate string) bool {
+	candidate = executableBasename(candidate)
+	if candidate == "" {
+		return false
+	}
+	for _, allowed := range ctx.Commands {
+		if executableBasename(allowed) == candidate {
+			return true
+		}
+	}
+	return false
+}
+
+func normalizeDomain(v string) string {
+	return strings.ToLower(strings.TrimRight(strings.TrimSpace(v), "."))
+}
+
+func normalizeCasefolded(v string) string {
+	return strings.ToLower(strings.TrimSpace(v))
+}
+
+// executableBasename returns the lowercased basename of the first whitespace-
+// separated token (the executable), splitting on both / and \.
+func executableBasename(command string) string {
+	fields := strings.Fields(command)
+	if len(fields) == 0 {
+		return ""
+	}
+	exe := fields[0]
+	if i := strings.LastIndexAny(exe, `/\`); i >= 0 {
+		exe = exe[i+1:]
+	}
+	return strings.ToLower(strings.TrimSpace(exe))
+}