fix: unify timestamp format to ISO 8601 for correct timezone display

.gitignore

@@ -57,3 +57,4 @@ lab/output/
 
 # opensrc - source code for packages
 opensrc/
+AGENTS.md

CLAUDE.md

@@ -125,6 +125,14 @@ Types are generated to `app/services/type.ts` from the database.
 
 **CamelCasePlugin と `sql` テンプレート**: `sql` テンプレートリテラル内の識別子は CamelCasePlugin で変換されない。`sql` 内でカラムを参照するときは `sql.ref('tableName.columnName')` を使うこと。
 
+### 日時・タイムゾーンの原則
+
+- **DB 保存形式**: ISO 8601（`2026-03-16T02:56:35Z`）。Z付きで保存し、ローカルタイム形式（`2026-03-16 02:56:35`）は使わない
+- **DB から読んだ日時のパース**: 必ず `dayjs.utc(value)` を使う。`dayjs(value)` はローカルタイムとして解釈されるため、タイムゾーン変換が正しく動かない
+- **表示層でのタイムゾーン変換**: `dayjs.utc(value).tz(timezone)` のパターンを使う
+- **batch での書き込み**: GitHub API から取得した ISO 8601 文字列をそのまま DB に保存する。独自のフォーマット変換をかけない
+- **`timeFormatTz`**（`batch/helper/timeformat.ts`）: レポートやスプレッドシート出力用。内部で `dayjs.utc()` を使用済み
+
 ### Path Aliases
 
 Use `~/` prefix for imports from `app/` directory:
@@ -218,7 +226,7 @@ Org-scoped tables (have `organizationId` column): `companyGithubUsers`, `exportS
 
 ### Source Code Reference
 
-Source code for dependencies is available in `opensrc/` for deeper understanding of implementation details. See `opensrc/sources.json` for the list of available packages.
+Source code for dependencies is available in `opensrc/` for deeper understanding of implementation details. See `opensrc/sources.json` for the list of available packages and their versions. Use this source code when you need to understand how a package works internally, not just its types/interface.
 
 ```bash
 npx opensrc <package>           # npm package (e.g., npx opensrc zod)

app/components/size-badge-popover.tsx

@@ -242,7 +242,7 @@ export function SizeBadgePopover({
                     </AvatarFallback>
                   </Avatar>
                 )}
-                {feedbackName} · {dayjs(feedbackAt).fromNow()}
+                {feedbackName} · {dayjs.utc(feedbackAt).fromNow()}
               </span>
             )}
             <Button

app/libs/business-hours.ts

@@ -72,8 +72,8 @@ export const calculateBusinessHours = (
   end: string,
   timezone = 'Asia/Tokyo',
 ): number => {
-  const startDate = dayjs(start).tz(timezone)
-  const endDate = dayjs(end).tz(timezone)
+  const startDate = dayjs.utc(start).tz(timezone)
+  const endDate = dayjs.utc(end).tz(timezone)
 
   if (!startDate.isBefore(endDate)) return 0
 
@@ -127,3 +127,18 @@ export const calculateBusinessHours = (
 
   return totalHours
 }
+
+/**
+ * 2つの日時間の差を日数で返す（営業時間 or カレンダー時間）
+ */
+export const diffInDays = (
+  start: string,
+  end: string,
+  businessDaysOnly: boolean,
+  timezone = 'Asia/Tokyo',
+): number => {
+  const hours = businessDaysOnly
+    ? calculateBusinessHours(start, end, timezone)
+    : dayjs.utc(end).diff(dayjs.utc(start), 'hour', true)
+  return hours / 24
+}

app/routes/$orgSlug/+components/pr-block.tsx

@@ -77,7 +77,7 @@ function getSizeColor(complexity: string | null): BlockColor {
 }
 
 function getAgeColor(createdAt: string): BlockColor {
-  const days = dayjs().diff(dayjs(createdAt), 'day', true)
+  const days = dayjs().diff(dayjs.utc(createdAt), 'day', true)
   for (const t of AGE_THRESHOLDS) {
     if (days < t.maxDays) return { bg: t.bg, ring: t.ring, bgFaint: t.bgFaint }
   }
@@ -126,7 +126,7 @@ export function PRPopoverContent({
   showAuthor?: boolean
   reviewState?: string
 }) {
-  const ageDays = Math.floor(dayjs().diff(dayjs(pr.createdAt), 'day', true))
+  const ageDays = Math.floor(dayjs().diff(dayjs.utc(pr.createdAt), 'day', true))
   const stateInfo = reviewState ? REVIEW_STATE_STYLE[reviewState] : null
   return (
     <div className="space-y-1">

app/routes/$orgSlug/analysis/feedbacks/_index/+components/feedback-columns.tsx

@@ -132,7 +132,7 @@ export const feedbackColumns: ColumnDef<FeedbackRow, unknown>[] = [
     header: 'Updated',
     cell: (info) => (
       <span className="text-muted-foreground text-sm text-nowrap">
-        {dayjs(info.getValue()).fromNow()}
+        {dayjs.utc(info.getValue()).fromNow()}
       </span>
     ),
     enableSorting: true,

app/routes/$orgSlug/analysis/feedbacks/_index/index.tsx

@@ -74,7 +74,7 @@ export const loader = async ({ request, context }: Route.LoaderArgs) => {
   const sinceDate =
     periodMonths === 'all'
       ? '2000-01-01T00:00:00.000Z'
-      : dayjs().subtract(periodMonths, 'month').startOf('day').toISOString()
+      : dayjs.utc().subtract(periodMonths, 'month').startOf('day').toISOString()
 
   const page = Number(url.searchParams.get('page') || '1')
   const perPage = Number(url.searchParams.get('per_page') || '20')

app/routes/$orgSlug/analysis/reviews/index.tsx

@@ -65,7 +65,7 @@ export const loader = async ({ request, context }: Route.LoaderArgs) => {
   const sinceDate =
     periodMonths === 'all'
       ? '2000-01-01T00:00:00.000Z'
-      : dayjs().subtract(periodMonths, 'month').startOf('day').toISOString()
+      : dayjs.utc().subtract(periodMonths, 'month').startOf('day').toISOString()
 
   const teams = await listTeams(organization.id)
 

app/routes/$orgSlug/settings/data-management/index.tsx

@@ -157,7 +157,8 @@ function RefreshSection({
         <Alert>
           <AlertDescription>
             Scheduled at{' '}
-            {dayjs(refreshRequestedAt)
+            {dayjs
+              .utc(refreshRequestedAt)
               .tz(timezone)
               .format('YYYY-MM-DD HH:mm:ss')}
             . It will run on the next crawl job.

app/routes/$orgSlug/settings/repositories.add/+components/repository-item.tsx

@@ -30,7 +30,7 @@ export const RepositoryItem = ({
       )}
       <div className="text-muted-foreground">·</div>
       <div className="text-muted-foreground text-xs">
-        {dayjs(repo.pushedAt).fromNow()}
+        {dayjs.utc(repo.pushedAt).fromNow()}
       </div>
 
       <div className="flex-1" />

app/routes/$orgSlug/throughput/deployed/+functions/queries.server.ts

@@ -1,6 +1,5 @@
 import { pipe, sortBy } from 'remeda'
-import { calculateBusinessHours } from '~/app/libs/business-hours'
-import dayjs from '~/app/libs/dayjs'
+import { diffInDays } from '~/app/libs/business-hours'
 import { excludeBots } from '~/app/libs/tenant-query.server'
 import { getTenantDb } from '~/app/services/tenant-db.server'
 import type { OrganizationId } from '~/app/types/organization'
@@ -73,23 +72,15 @@ export const getDeployedPullRequestReport = async (
   return pipe(
     pullrequests.map((pr) => {
       const createAndDeployDiff = pr.releasedAt
-        ? (businessDaysOnly
-            ? calculateBusinessHours(
-                pr.firstCommittedAt ?? pr.pullRequestCreatedAt,
-                pr.releasedAt,
-              )
-            : dayjs(pr.releasedAt).diff(
-                dayjs(pr.firstCommittedAt ?? pr.pullRequestCreatedAt),
-                'hour',
-                true,
-              )) / 24
+        ? diffInDays(
+            pr.firstCommittedAt ?? pr.pullRequestCreatedAt,
+            pr.releasedAt,
+            businessDaysOnly,
+          )
         : null
       const deployTime =
         pr.mergedAt && pr.releasedAt
-          ? (businessDaysOnly
-              ? calculateBusinessHours(pr.mergedAt, pr.releasedAt)
-              : dayjs(pr.releasedAt).diff(dayjs(pr.mergedAt), 'hour', true)) /
-            24
+          ? diffInDays(pr.mergedAt, pr.releasedAt, businessDaysOnly)
           : null
       const achievement =
         createAndDeployDiff !== null ? createAndDeployDiff < objective : false

app/routes/$orgSlug/throughput/merged/+functions/queries.server.ts

@@ -1,6 +1,5 @@
 import { pipe, sortBy } from 'remeda'
-import { calculateBusinessHours } from '~/app/libs/business-hours'
-import dayjs from '~/app/libs/dayjs'
+import { diffInDays } from '~/app/libs/business-hours'
 import { excludeBots } from '~/app/libs/tenant-query.server'
 import { getTenantDb } from '~/app/services/tenant-db.server'
 import type { OrganizationId } from '~/app/types/organization'
@@ -71,16 +70,11 @@ export const getMergedPullRequestReport = async (
   return pipe(
     pullrequests.map((pr) => {
       const createAndMergeDiff = pr.mergedAt
-        ? (businessDaysOnly
-            ? calculateBusinessHours(
-                pr.firstCommittedAt ?? pr.pullRequestCreatedAt,
-                pr.mergedAt,
-              )
-            : dayjs(pr.mergedAt).diff(
-                dayjs(pr.firstCommittedAt ?? pr.pullRequestCreatedAt),
-                'hour',
-                true,
-              )) / 24
+        ? diffInDays(
+            pr.firstCommittedAt ?? pr.pullRequestCreatedAt,
+            pr.mergedAt,
+            businessDaysOnly,
+          )
         : null
       const achievement =
         createAndMergeDiff !== null ? createAndMergeDiff < objective : false

app/routes/$orgSlug/throughput/ongoing/+functions/queries.server.ts

@@ -1,5 +1,5 @@
 import { pipe, sortBy } from 'remeda'
-import { calculateBusinessHours } from '~/app/libs/business-hours'
+import { diffInDays } from '~/app/libs/business-hours'
 import dayjs from '~/app/libs/dayjs'
 import { excludeBots } from '~/app/libs/tenant-query.server'
 import { getTenantDb } from '~/app/services/tenant-db.server'
@@ -71,17 +71,14 @@ export const getOngoingPullRequestReport = async (
     ])
     .execute()
 
-  const now = new Date().toISOString()
+  const now = dayjs.utc().toISOString()
 
   return pipe(
     pullrequests.map((pr) => {
       const startDate = pr.firstCommittedAt ?? pr.pullRequestCreatedAt
-      const diffHours = businessDaysOnly
-        ? calculateBusinessHours(startDate, now)
-        : dayjs(now).diff(dayjs(startDate), 'hour', true)
       return {
         ...pr,
-        createAndNowDiff: diffHours / 24,
+        createAndNowDiff: diffInDays(startDate, now, businessDaysOnly),
       }
     }),
     sortBy((pr) => (pr.createAndNowDiff ? -pr.createAndNowDiff : 0)),

app/routes/$orgSlug/workload/$login/index.tsx

@@ -168,16 +168,19 @@ export default function MemberWeeklyPage({
       holiday: holidays[dateStr] ?? null,
       created: createdPRs.filter(
         (pr) =>
-          dayjs(pr.pullRequestCreatedAt).tz(timezone).format('YYYY-MM-DD') ===
-          dateStr,
+          dayjs
+            .utc(pr.pullRequestCreatedAt)
+            .tz(timezone)
+            .format('YYYY-MM-DD') === dateStr,
       ),
       merged: mergedPRs.filter(
         (pr) =>
-          dayjs(pr.mergedAt).tz(timezone).format('YYYY-MM-DD') === dateStr,
+          dayjs.utc(pr.mergedAt).tz(timezone).format('YYYY-MM-DD') === dateStr,
       ),
       reviewed: reviews.filter(
         (r) =>
-          dayjs(r.submittedAt).tz(timezone).format('YYYY-MM-DD') === dateStr,
+          dayjs.utc(r.submittedAt).tz(timezone).format('YYYY-MM-DD') ===
+          dateStr,
       ),
     }
   })
@@ -421,7 +424,8 @@ export default function MemberWeeklyPage({
               title={pr.title}
               url={pr.url}
               complexity={pr.complexity}
-              date={dayjs(pr.pullRequestCreatedAt)
+              date={dayjs
+                .utc(pr.pullRequestCreatedAt)
                 .tz(timezone)
                 .format('M/D HH:mm')}
             />
@@ -443,7 +447,7 @@ export default function MemberWeeklyPage({
               title={pr.title}
               url={pr.url}
               complexity={pr.complexity}
-              date={dayjs(pr.mergedAt).tz(timezone).format('M/D HH:mm')}
+              date={dayjs.utc(pr.mergedAt).tz(timezone).format('M/D HH:mm')}
               extra={pr.totalTime ? `${pr.totalTime.toFixed(1)}d` : undefined}
             />
           ))}
@@ -465,7 +469,7 @@ export default function MemberWeeklyPage({
               url={r.url}
               complexity={r.complexity}
               author={r.author}
-              date={dayjs(r.submittedAt).tz(timezone).format('M/D HH:mm')}
+              date={dayjs.utc(r.submittedAt).tz(timezone).format('M/D HH:mm')}
               reviewState={r.state}
             />
           ))}

app/routes/$orgSlug/workload/+components/team-stacks-chart.tsx

@@ -37,7 +37,7 @@ function sortBySize(prs: StackPR[]): StackPR[] {
 // --- Age mode ---
 
 function getAgeDays(pr: StackPR): number {
-  return dayjs().diff(dayjs(pr.createdAt), 'day', true)
+  return dayjs().diff(dayjs.utc(pr.createdAt), 'day', true)
 }
 
 function sortByAge(prs: StackPR[]): StackPR[] {

batch/bizlogic/cycletime.ts

@@ -11,7 +11,9 @@ export const codingTime = ({
 }: codingTimeProps) => {
   if (firstCommittedAt && pullRequestCreatedAt) {
     return Math.abs(
-      dayjs(pullRequestCreatedAt).diff(firstCommittedAt, 'days', true),
+      dayjs
+        .utc(pullRequestCreatedAt)
+        .diff(dayjs.utc(firstCommittedAt), 'days', true),
     )
   }
   return null
@@ -29,11 +31,15 @@ export const pickupTime = ({
 }: pickupTimeProps) => {
   if (firstReviewedAt) {
     return Math.abs(
-      dayjs(firstReviewedAt).diff(pullRequestCreatedAt, 'days', true),
+      dayjs
+        .utc(firstReviewedAt)
+        .diff(dayjs.utc(pullRequestCreatedAt), 'days', true),
     )
   }
   if (mergedAt) {
-    return Math.abs(dayjs(mergedAt).diff(pullRequestCreatedAt, 'days', true))
+    return Math.abs(
+      dayjs.utc(mergedAt).diff(dayjs.utc(pullRequestCreatedAt), 'days', true),
+    )
   }
   return null
 }
@@ -44,7 +50,9 @@ interface reviewTimeProps {
 }
 export const reviewTime = ({ firstReviewedAt, mergedAt }: reviewTimeProps) => {
   if (firstReviewedAt && mergedAt) {
-    return Math.abs(dayjs(mergedAt).diff(firstReviewedAt, 'days', true))
+    return Math.abs(
+      dayjs.utc(mergedAt).diff(dayjs.utc(firstReviewedAt), 'days', true),
+    )
   }
   return null
 }
@@ -55,7 +63,9 @@ interface deployTimeProps {
 }
 export const deployTime = ({ mergedAt, releasedAt }: deployTimeProps) => {
   if (mergedAt && releasedAt) {
-    return Math.abs(dayjs(releasedAt).diff(mergedAt, 'days', true))
+    return Math.abs(
+      dayjs.utc(releasedAt).diff(dayjs.utc(mergedAt), 'days', true),
+    )
   }
   return null
 }
@@ -83,12 +93,12 @@ export const totalTime = ({
       releasedAt,
     ],
     filter((x) => !!x),
-    sortBy((x) => dayjs(x).unix()),
+    sortBy((x) => dayjs.utc(x).unix()),
   )
   const firstTime = first(times)
   const lastTime = last(times)
   if (firstTime && lastTime) {
-    return dayjs(lastTime).diff(firstTime, 'days', true)
+    return dayjs.utc(lastTime).diff(dayjs.utc(firstTime), 'days', true)
   }
   return null
 }