feat(campaign): add shared read-only WindowTimeline component

A domain-agnostic horizontal timeline: an axis over the service-cycle window
with offset-positioned markers, stable per-colorKey colours, optional badges,
hover tooltips, click callbacks, and an optional legend. Shared base for the
plan preview (09) and process timeline (10). (v0.6 ticket 08)

frontend/web/src/components/WindowTimeline.tsx

@@ -0,0 +1,122 @@
+import { Tooltip } from 'antd'
+import type { ReactNode } from 'react'
+import { colors, fontSizes } from '../tokens'
+
+// A read-only horizontal timeline: one axis representing a service-cycle window,
+// with markers positioned by their window offset. It is domain-agnostic — the
+// ②计划预览 and ④过程时间轴 callers each adapt their data into markers. Colours
+// are assigned stably per `colorKey` (same key → same colour, order-independent).
+
+export interface TimelineMarker {
+  key: string
+  offsetSeconds: number
+  colorKey: string
+  label?: string
+  badge?: number | string
+  tooltip: ReactNode
+  onClick?: () => void
+}
+
+interface WindowTimelineProps {
+  windowSeconds: number
+  markers: TimelineMarker[]
+  /** colorKey → legend display name; falls back to the raw key. */
+  colorLabels?: Record<string, string>
+  showLegend?: boolean
+  height?: number
+}
+
+const PALETTE = [
+  '#1677ff', '#52c41a', '#fa8c16', '#722ed1',
+  '#13c2c2', '#eb2f96', '#faad14', '#2f54eb',
+]
+
+const TICK_COUNT = 6
+
+function fmtTick(seconds: number): string {
+  if (seconds < 3600) return `${Math.round(seconds / 60)}m`
+  const h = seconds / 3600
+  return `${Number.isInteger(h) ? h : h.toFixed(1)}h`
+}
+
+export default function WindowTimeline({
+  windowSeconds, markers, colorLabels, showLegend = false, height = 64,
+}: WindowTimelineProps) {
+  const window = windowSeconds > 0 ? windowSeconds : 1
+  const uniqueKeys = Array.from(new Set(markers.map((m) => m.colorKey))).sort()
+  const colorOf = (key: string) => PALETTE[Math.max(0, uniqueKeys.indexOf(key)) % PALETTE.length]
+  const leftPct = (offset: number) => `${Math.min(1, Math.max(0, offset / window)) * 100}%`
+
+  const ticks = Array.from({ length: TICK_COUNT + 1 }, (_, i) => i / TICK_COUNT)
+
+  return (
+    <div>
+      <div style={{ position: 'relative', height, margin: '0 12px' }}>
+        <div style={{
+          position: 'absolute', left: 0, right: 0, top: '50%',
+          height: 2, background: colors.border,
+        }} />
+
+        {ticks.map((t) => (
+          <div key={t} style={{ position: 'absolute', left: `${t * 100}%`, top: 0, bottom: 0 }}>
+            <div style={{
+              position: 'absolute', top: '50%', width: 1, height: 8,
+              marginTop: -4, background: colors.textMuted,
+            }} />
+            <span style={{
+              position: 'absolute', top: '50%', marginTop: 8, transform: 'translateX(-50%)',
+              fontSize: fontSizes.meta, color: colors.textMuted, whiteSpace: 'nowrap',
+            }}>
+              {fmtTick(t * window)}
+            </span>
+          </div>
+        ))}
+
+        {markers.map((m) => {
+          const c = colorOf(m.colorKey)
+          return (
+            <Tooltip key={m.key} title={m.tooltip}>
+              <div
+                onClick={m.onClick}
+                style={{
+                  position: 'absolute', left: leftPct(m.offsetSeconds), top: '50%',
+                  transform: 'translate(-50%, -50%)',
+                  cursor: m.onClick ? 'pointer' : 'default',
+                }}
+              >
+                {m.label != null ? (
+                  <span style={{
+                    padding: '1px 6px', borderRadius: 10, background: c, color: '#fff',
+                    fontSize: fontSizes.meta, whiteSpace: 'nowrap',
+                  }}>
+                    {m.label}
+                    {m.badge != null && <b style={{ marginLeft: 4 }}>{m.badge}</b>}
+                  </span>
+                ) : (
+                  <span style={{
+                    display: 'block', width: 12, height: 12, borderRadius: '50%',
+                    background: c, border: '2px solid #fff', boxShadow: '0 0 0 1px rgba(0,0,0,0.1)',
+                  }} />
+                )}
+              </div>
+            </Tooltip>
+          )
+        })}
+      </div>
+
+      {showLegend && uniqueKeys.length > 0 && (
+        <div style={{
+          display: 'flex', flexWrap: 'wrap', gap: 12, marginTop: 24,
+          fontSize: fontSizes.meta, color: colors.textSecondary,
+        }}>
+          {uniqueKeys.map((k) => (
+            <span key={k} style={{ display: 'inline-flex', alignItems: 'center', gap: 4 }}>
+              <span style={{ width: 10, height: 10, borderRadius: 2, background: colorOf(k) }} />
+              {colorLabels?.[k] ?? k}
+            </span>
+          ))}
+        </div>
+      )}
+    </div>
+  )
+}