refactor(frontend): extract attention scorer and shared type guards

v2/src/lib/utils/attention-scorer.ts

@@ -0,0 +1,68 @@
+// Attention scoring — pure function extracted from health store
+// Determines which project needs attention most urgently
+
+import type { ActivityState } from '../stores/health.svelte';
+
+// Attention score weights (higher = more urgent)
+const SCORE_STALLED = 100;
+const SCORE_ERROR = 90;
+const SCORE_CONTEXT_CRITICAL = 80; // >90% context
+const SCORE_FILE_CONFLICT = 70;
+const SCORE_CONTEXT_HIGH = 40; // >75% context
+
+export interface AttentionInput {
+  sessionStatus: string | undefined;
+  sessionError: string | undefined;
+  activityState: ActivityState;
+  idleDurationMs: number;
+  contextPressure: number | null;
+  fileConflictCount: number;
+  externalConflictCount: number;
+}
+
+export interface AttentionResult {
+  score: number;
+  reason: string | null;
+}
+
+/** Score how urgently a project needs human attention. Highest-priority signal wins. */
+export function scoreAttention(input: AttentionInput): AttentionResult {
+  if (input.sessionStatus === 'error') {
+    return {
+      score: SCORE_ERROR,
+      reason: `Error: ${input.sessionError?.slice(0, 60) ?? 'Unknown'}`,
+    };
+  }
+
+  if (input.activityState === 'stalled') {
+    const mins = Math.floor(input.idleDurationMs / 60_000);
+    return {
+      score: SCORE_STALLED,
+      reason: `Stalled — ${mins} min since last activity`,
+    };
+  }
+
+  if (input.contextPressure !== null && input.contextPressure > 0.9) {
+    return {
+      score: SCORE_CONTEXT_CRITICAL,
+      reason: `Context ${Math.round(input.contextPressure * 100)}% — near limit`,
+    };
+  }
+
+  if (input.fileConflictCount > 0) {
+    const extNote = input.externalConflictCount > 0 ? ` (${input.externalConflictCount} external)` : '';
+    return {
+      score: SCORE_FILE_CONFLICT,
+      reason: `${input.fileConflictCount} file conflict${input.fileConflictCount > 1 ? 's' : ''}${extNote}`,
+    };
+  }
+
+  if (input.contextPressure !== null && input.contextPressure > 0.75) {
+    return {
+      score: SCORE_CONTEXT_HIGH,
+      reason: `Context ${Math.round(input.contextPressure * 100)}%`,
+    };
+  }
+
+  return { score: 0, reason: null };
+}