feat(web): run-eta helper + bigger pill-shaped add buttons

estimateRunDuration() computes a per-run ETA from a target count, a
fire time, and an assumed per-account send rate (40/min, mirroring
the bot env). Adds a 15% buffer with a 1-minute floor. Pure helper,
covered by 6 round-trip tests including the rate-defaults path.

Header CTA buttons on /accounts and /reminders are now size="lg"
rounded-full pills with a shadow that lifts on hover. Mobile shows
just the plus icon (label collapses) so the button doesn't dominate
narrow screens.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/app/reminders/page.tsx

@@ -181,14 +181,18 @@ export default async function RemindersPage({ searchParams }: PageProps) {
 
   return (
     <div className="px-4 py-6 sm:px-6 sm:py-8 max-w-5xl mx-auto space-y-6">
-      <div className="flex items-center justify-between gap-4">
+      <div className="flex items-center justify-end sm:justify-between gap-4">
         {/* Hidden on mobile — the top header already shows "Reminders". */}
         <h1 className="hidden sm:block text-2xl font-semibold tracking-tight">Reminders</h1>
-        <Button asChild size="sm">
+        <Button
+          asChild
+          size="lg"
+          className="rounded-full shadow-md hover:shadow-lg transition-all px-6 gap-2 font-semibold"
+        >
           {/* eslint-disable-next-line @typescript-eslint/no-explicit-any */}
-          <Link href={"/reminders/new" as any}>
+          <Link href={"/reminders/new" as any} aria-label="New reminder">
-            <PlusIcon />
+            <PlusIcon className="size-5" />
-            New Reminder
+            <span className="hidden sm:inline">New Reminder</span>
           </Link>
         </Button>
       </div>

apps/web/src/components/accounts-list-view.tsx

@@ -33,11 +33,15 @@ export function AccountsListView({ accounts }: AccountsListViewProps) {
       <div className="flex items-center justify-end sm:justify-between gap-4">
         {/* Hidden on mobile — the top header already shows "Accounts". */}
         <h1 className="hidden sm:block text-2xl font-semibold tracking-tight">Accounts</h1>
-        <Button asChild size="sm">
+        <Button
+          asChild
+          size="lg"
+          className="rounded-full shadow-md hover:shadow-lg transition-all px-6 gap-2 font-semibold"
+        >
           {/* eslint-disable-next-line @typescript-eslint/no-explicit-any */}
-          <Link href={"/accounts/new" as any}>
+          <Link href={"/accounts/new" as any} aria-label="Add account">
-            <PlusIcon />
+            <PlusIcon className="size-5" />
-            Add Account
+            <span className="hidden sm:inline">Add Account</span>
           </Link>
         </Button>
       </div>

apps/web/src/lib/run-eta.test.ts

@@ -0,0 +1,56 @@
+import { describe, it, expect } from "vitest";
+import { estimateRunDuration, ASSUMED_RATE_PER_MINUTE } from "./run-eta";
+
+describe("estimateRunDuration", () => {
+  it("uses targetCount/rate plus a 15% buffer, ceiling-rounded to whole minutes", () => {
+    const r = estimateRunDuration({
+      targetCount: 1000,
+      ratePerMinute: 40,
+      fireAt: new Date("2026-05-13T09:00:00.000+08:00"),
+    });
+    // 1000 / 40 = 25 min; +15% = 28.75 → ceil = 29
+    expect(r.durationMinutes).toBe(29);
+    expect(r.estimatedFinishAt.toISOString()).toBe(
+      new Date("2026-05-13T09:29:00.000+08:00").toISOString(),
+    );
+  });
+
+  it("returns a 1-minute floor for very small runs", () => {
+    const r = estimateRunDuration({
+      targetCount: 1,
+      ratePerMinute: 40,
+      fireAt: new Date("2026-05-13T09:00:00.000+08:00"),
+    });
+    expect(r.durationMinutes).toBe(1);
+  });
+
+  it("returns 0 minutes and finishAt = fireAt when targetCount is 0", () => {
+    const fireAt = new Date("2026-05-13T09:00:00.000+08:00");
+    const r = estimateRunDuration({ targetCount: 0, ratePerMinute: 40, fireAt });
+    expect(r.durationMinutes).toBe(0);
+    expect(r.estimatedFinishAt.toISOString()).toBe(fireAt.toISOString());
+  });
+
+  it("throws when ratePerMinute is 0 or negative", () => {
+    expect(() =>
+      estimateRunDuration({ targetCount: 100, ratePerMinute: 0, fireAt: new Date() }),
+    ).toThrow();
+    expect(() =>
+      estimateRunDuration({ targetCount: 100, ratePerMinute: -1, fireAt: new Date() }),
+    ).toThrow();
+  });
+
+  it("falls back to ASSUMED_RATE_PER_MINUTE when ratePerMinute is omitted", () => {
+    const r = estimateRunDuration({
+      targetCount: ASSUMED_RATE_PER_MINUTE, // exactly one minute's worth at the assumed rate
+      fireAt: new Date("2026-05-13T09:00:00.000+08:00"),
+    });
+    // 40 / 40 = 1 min; +15% = 1.15 → ceil = 2 min
+    expect(r.durationMinutes).toBe(2);
+  });
+
+  it("exports a positive default rate constant", () => {
+    expect(typeof ASSUMED_RATE_PER_MINUTE).toBe("number");
+    expect(ASSUMED_RATE_PER_MINUTE).toBeGreaterThan(0);
+  });
+});

apps/web/src/lib/run-eta.ts

@@ -0,0 +1,39 @@
+/**
+ * Default per-account send rate, mirroring `BOT_MAX_SEND_PER_MINUTE`
+ * in the bot env. The web bundle hardcodes this — operators who tune
+ * the bot env are expected to redeploy web with the matching value.
+ */
+export const ASSUMED_RATE_PER_MINUTE = 40;
+
+const ETA_BUFFER = 1.15;
+
+/**
+ * Pure ETA helper. Given a target count and a fire time, returns the
+ * estimated duration in whole minutes and the projected finish
+ * timestamp.
+ *
+ * Calculation:
+ *   ceil((targetCount / ratePerMinute) * 1.15)   minutes
+ *   estimatedFinishAt = fireAt + that many minutes
+ *
+ * Floor of 1 minute when targetCount > 0 (anything non-zero takes at
+ * least a minute to feel real). Returns 0 minutes when targetCount
+ * is zero — the run is a no-op.
+ */
+export function estimateRunDuration(opts: {
+  targetCount: number;
+  ratePerMinute?: number;
+  fireAt: Date;
+}): { durationMinutes: number; estimatedFinishAt: Date } {
+  const rate = opts.ratePerMinute ?? ASSUMED_RATE_PER_MINUTE;
+  if (rate <= 0) throw new Error("ratePerMinute must be > 0");
+  if (opts.targetCount <= 0) {
+    return { durationMinutes: 0, estimatedFinishAt: new Date(opts.fireAt) };
+  }
+  const raw = (opts.targetCount / rate) * ETA_BUFFER;
+  const durationMinutes = Math.max(1, Math.ceil(raw));
+  const estimatedFinishAt = new Date(
+    opts.fireAt.getTime() + durationMinutes * 60_000,
+  );
+  return { durationMinutes, estimatedFinishAt };
+}