feat: add coordination-ROI band to member Work History

Surfaces "rework saved" at the top of the teammate Work History dialog:
a transparent heuristic over collisions Hermes caught early (eligible =
gitOverlap or critical, with an intervention), credit split across
involved engineers. Shows hard counts (clashes caught, conflict-free
files) plus an info-tooltip breakdown of the estimate.

- shared: optional MemberWorkHistoryRoi field (back-compat, self-zeroes)
- backend: query collisions + interventions in getMemberWorkHistory,
  computeRoi helper
- frontend: RoiBand + RoiTooltip components, hidden when no clashes

Implements docs/plans/work-history-roi.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LuV8W8oNYRsDWKoqK8Mkqc

backend/src/activity/member-history.ts

@@ -1,4 +1,10 @@
-import type { EngineerContext, MemberWorkHistory, MemberWorkHistoryFile } from '@podman/shared';
+import type {
+  Collision,
+  EngineerContext,
+  MemberWorkHistory,
+  MemberWorkHistoryFile,
+  MemberWorkHistoryRoi,
+} from '@podman/shared';
 import { getDb } from '../memory/db.js';
 import { parseGitStatusPath } from '../graph/live.js';
 
@@ -80,7 +86,7 @@ export async function getMemberWorkHistory(
   const limit = Math.min(Math.max(options.limit ?? 80, 10), 200);
   const since = new Date(Date.now() - windowHours * 60 * 60 * 1000).toISOString();
 
-  const [observations, gitState] = await Promise.all([
+  const [observations, gitState, collisions, interventions] = await Promise.all([
     db
       .collection<EngineerContext>('observations')
       .find({ podId, observedAt: { $gte: since } }, { projection: { _id: 0 } })
@@ -91,6 +97,16 @@ export async function getMemberWorkHistory(
       podId,
       name: { $regex: `^${member.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}$`, $options: 'i' },
     }),
+    db
+      .collection<Collision>('collisions')
+      .find({ podId, detectedAt: { $gte: since } }, { projection: { _id: 0 } })
+      .sort({ detectedAt: -1 })
+      .limit(200)
+      .toArray(),
+    db
+      .collection<{ collisionId: string }>('interventions')
+      .find({ podId }, { projection: { collisionId: 1, _id: 0 } })
+      .toArray(),
   ]);
 
   const files = new Map<string, FileAccumulator>();
@@ -158,6 +174,9 @@ export async function getMemberWorkHistory(
 
   timeline.sort((a, b) => Date.parse(b.at) - Date.parse(a.at));
 
+  const interventionIds = new Set(interventions.map((i) => i.collisionId));
+  const roi = computeRoi(member, collisions, interventionIds, gitState?.changedFiles?.length ?? 0);
+
   return {
     podId,
     member,
@@ -170,5 +189,56 @@ export async function getMemberWorkHistory(
     },
     files: fileRows,
     timeline: timeline.slice(0, limit),
+    roi,
+  };
+}
+
+function computeRoi(
+  member: string,
+  collisions: Collision[],
+  interventionCollisionIds: Set<string>,
+  changedFileCount: number,
+): MemberWorkHistoryRoi {
+  const involved = (c: Collision) =>
+    c.engineers?.some((e) => sameMember(e, member)) ||
+    sameMember(c.researcher, member) ||
+    sameMember(c.editor, member);
+
+  const eligible = collisions.filter(
+    (c) =>
+      involved(c) &&
+      interventionCollisionIds.has(c.id) &&
+      (c.gitOverlap === true || c.severity === 'critical'),
+  );
+
+  const weightOf = (c: Collision): { label: string; minutes: number } => {
+    if (c.overlapKind === 'research') return { label: 'research overlap', minutes: 10 };
+    if (c.severity === 'critical') return { label: 'critical same-file', minutes: 45 };
+    if (c.severity === 'warn') return { label: 'warn same-file', minutes: 20 };
+    return { label: 'info same-file', minutes: 10 };
+  };
+
+  let savedMinutes = 0;
+  const groups = new Map<string, { count: number; minutesEach: number }>();
+  for (const c of eligible) {
+    const { label, minutes } = weightOf(c);
+    savedMinutes += minutes / Math.max(1, c.engineers?.length ?? 1);
+    const g = groups.get(label) ?? { count: 0, minutesEach: minutes };
+    g.count += 1;
+    groups.set(label, g);
+  }
+
+  const filesDeconflicted = new Set(eligible.map((c) => c.file)).size;
+  return {
+    savedMinutes: Math.round(savedMinutes),
+    clashesCaught: eligible.length,
+    filesDeconflicted,
+    conflictFreeFiles: Math.max(0, changedFileCount - filesDeconflicted),
+    totalFiles: changedFileCount,
+    breakdown: [...groups.entries()].map(([label, g]) => ({
+      label,
+      count: g.count,
+      minutesEach: g.minutesEach,
+    })),
   };
 }

frontend/src/components/PodView.tsx

@@ -9,6 +9,7 @@ import {
   EyeIcon,
   GitBranchIcon,
   ExternalLinkIcon,
+  InfoIcon,
   MessageSquareIcon,
   MicIcon,
   MicOffIcon,
@@ -33,6 +34,7 @@ import type {
   MemberWorkHistory,
   MemberWorkHistoryEvent,
   MemberWorkHistoryFile,
+  MemberWorkHistoryRoi,
   Pod,
   PodActivityEvent,
   PodActivityKind,
@@ -1034,6 +1036,7 @@ function WorkHistoryDialog({
 
         {history && !loading && !error && (
           <div className="flex flex-col gap-5">
+            <RoiBand roi={history.roi} />
             <div className="grid gap-2 sm:grid-cols-3">
               <HistoryStat label="Files" value={history.totals.files} />
               <HistoryStat label="Screen logs" value={history.totals.observations} />
@@ -1090,6 +1093,88 @@ function WorkHistoryDialog({
   );
 }
 
+function formatSaved(minutes: number): string {
+  if (minutes < 60) return `~${minutes}m`;
+  const h = Math.floor(minutes / 60);
+  const m = minutes % 60;
+  return m ? `~${h}h ${m}m` : `~${h}h`;
+}
+
+function RoiTooltip({ roi }: { roi: MemberWorkHistoryRoi }) {
+  return (
+    <Tooltip>
+      <TooltipTrigger asChild>
+        <button
+          type="button"
+          aria-label="How rework saved is estimated"
+          className="text-muted-foreground transition-colors hover:text-foreground"
+        >
+          <InfoIcon className="size-3.5" />
+        </button>
+      </TooltipTrigger>
+      <TooltipContent className="max-w-64">
+        <div className="flex flex-col gap-1">
+          <p className="font-medium">Estimated rework saved</p>
+          {roi.breakdown.length ? (
+            roi.breakdown.map((row) => (
+              <p key={row.label} className="font-mono text-[0.7rem]">
+                {row.count} × {row.minutesEach}m · {row.label}
+              </p>
+            ))
+          ) : (
+            <p className="text-[0.7rem]">No eligible clashes.</p>
+          )}
+          <p className="text-[0.68rem] text-muted-foreground">
+            credit split across engineers · est. only
+          </p>
+        </div>
+      </TooltipContent>
+    </Tooltip>
+  );
+}
+
+function RoiBand({ roi }: { roi?: MemberWorkHistoryRoi }) {
+  if (!roi || roi.clashesCaught === 0) return null;
+  const conflictFree = roi.totalFiles
+    ? Math.round((roi.conflictFreeFiles / roi.totalFiles) * 100)
+    : 100;
+  return (
+    <section className="rounded-lg border bg-primary/5 p-4">
+      <div className="flex flex-wrap items-end justify-between gap-3">
+        <div>
+          <div className="flex items-center gap-1.5">
+            <p className="font-mono text-2xl font-semibold">{formatSaved(roi.savedMinutes)}</p>
+            <span className="text-sm text-muted-foreground">rework saved</span>
+            <RoiTooltip roi={roi} />
+          </div>
+          <p className="mt-0.5 text-xs text-muted-foreground">
+            estimated · clashes caught pre-commit
+          </p>
+        </div>
+        <div className="text-right">
+          <p className="font-mono text-lg font-medium">{roi.clashesCaught}</p>
+          <p className="text-xs text-muted-foreground">clashes caught early</p>
+        </div>
+      </div>
+      {roi.totalFiles > 0 && (
+        <>
+          <div className="mt-3 h-2 overflow-hidden rounded-full bg-muted">
+            <div
+              className="h-full rounded-full bg-primary"
+              style={{ width: `${conflictFree}%` }}
+              aria-label={`${roi.conflictFreeFiles} of ${roi.totalFiles} files conflict-free`}
+            />
+          </div>
+          <p className="mt-1.5 text-[0.68rem] text-muted-foreground">
+            conflict-free: {roi.conflictFreeFiles} of {roi.totalFiles} files ·{' '}
+            {roi.filesDeconflicted} auto-deconflicted
+          </p>
+        </>
+      )}
+    </section>
+  );
+}
+
 function HistoryStat({ label, value }: { label: string; value: number }) {
   return (
     <div className="rounded-lg border bg-background px-3 py-2">

shared/src/index.ts

@@ -56,5 +56,6 @@ export type {
   MemberWorkHistory,
   MemberWorkHistoryEvent,
   MemberWorkHistoryFile,
+  MemberWorkHistoryRoi,
   MemberWorkHistorySource,
 } from './member-history.js';

shared/src/member-history.ts

@@ -33,4 +33,24 @@ export interface MemberWorkHistory {
   };
   files: MemberWorkHistoryFile[];
   timeline: MemberWorkHistoryEvent[];
+  /**
+   * Coordination ROI summary — clashes Hermes caught for this member. Optional
+   * so pods with no collisions / older payloads render without the band.
+   */
+  roi?: MemberWorkHistoryRoi;
+}
+
+export interface MemberWorkHistoryRoi {
+  /** Estimated rework minutes saved (heuristic, labeled "~/est." in UI). */
+  savedMinutes: number;
+  /** Eligible collisions caught early (hard count). */
+  clashesCaught: number;
+  /** Distinct files that hit an eligible clash. */
+  filesDeconflicted: number;
+  /** Member files in flight that never hit a clash. */
+  conflictFreeFiles: number;
+  /** Total member files in flight (git changedFiles). */
+  totalFiles: number;
+  /** Per-kind breakdown for the tooltip. */
+  breakdown: { label: string; count: number; minutesEach: number }[];
 }