refactor(01-02): decompose execution.tsx and automation.tsx into focused sub-components

- execution.tsx (1749 lines) -> 16 focused files under 300 lines each:
  TaskQueue, TaskInspector, TaskCreator, TaskComments, ApprovalList,
  ApprovalInspector, ActivityList, CostList, BudgetSummary, WorkspaceList,
  WorkspaceInspector, WorkspaceCreator, SecretCreator, SettingsPane,
  PendingReviewList, execution-utils
- automation.tsx (1697 lines) -> 6 focused files under 300 lines each:
  AutomationPanel, RuleCard, RuleEditor, WorkflowList, WorkflowEditor,
  automation-config
- Both original files replaced with backward-compatible re-exports
- All sub-components under 300 lines, TypeScript compilation passes

src/renderer/components/execution/ActivityList.tsx

@@ -0,0 +1,51 @@
+import { useMemo, useState } from "react"
+import { ArrowRight, Lightning, MagnifyingGlass } from "@phosphor-icons/react"
+import type { ActivityRecord } from "@shared/types"
+import { useT } from "../../i18n"
+import { formatTime } from "../../lib/formatters"
+import { ActionButton, EmptyState, ListFrame, ListRow, Select } from "../ui"
+import { ENTITY_ICONS, ENTITY_TYPE_OPTIONS } from "./execution-utils"
+
+export function ActivityList({ activity }: { activity: ActivityRecord[] }) {
+  const t = useT()
+  const [search, setSearch] = useState(""); const [entityFilter, setEntityFilter] = useState<string>("all"); const [visibleCount, setVisibleCount] = useState(100)
+  const filtered = useMemo(() => {
+    let result = activity
+    if (entityFilter !== "all") result = result.filter((e) => e.entityType === entityFilter)
+    if (search.trim()) { const q = search.toLowerCase(); result = result.filter((e) => e.action.toLowerCase().includes(q) || e.actor.toLowerCase().includes(q) || e.detail.toLowerCase().includes(q) || e.entityType.toLowerCase().includes(q)) }
+    return result
+  }, [activity, entityFilter, search])
+  const visible = filtered.slice(0, visibleCount)
+
+  if (activity.length === 0) return <EmptyState title={t("exec.noActivityYet")} />
+  return (
+    <div className="space-y-3">
+      <div className="flex items-center gap-3">
+        <div className="relative flex-1">
+          <MagnifyingGlass size={14} className="absolute left-3 top-1/2 -translate-y-1/2 text-[color:var(--muted)]" />
+          <input type="text" className="focus-ring w-full rounded-[8px] border border-[color:var(--line)] bg-[color:var(--panel)] py-2.5 pl-8 pr-3.5 text-[13px] text-[color:var(--text)] placeholder:text-[color:var(--muted)]" value={search} onChange={(e) => setSearch(e.target.value)} placeholder={t("exec.searchActivity")} />
+        </div>
+        <Select value={entityFilter} onChange={setEntityFilter} options={ENTITY_TYPE_OPTIONS.map((v) => ({ value: v, label: v === "all" ? t("exec.allTypes") : v }))} />
+      </div>
+      {visible.length === 0 ? <EmptyState title={t("exec.noMatchingActivity")} /> : (
+        <>
+          <ListFrame>
+            {visible.map((entry) => {
+              const EntityIcon = ENTITY_ICONS[entry.entityType] ?? Lightning
+              return (
+                <ListRow key={entry.id}>
+                  <div className="mb-2 flex items-center justify-between gap-3">
+                    <div className="flex items-center gap-2"><EntityIcon size={14} weight="duotone" className="text-[color:var(--muted)]" /><div className="text-[14px] text-[color:var(--text)]">{entry.action}</div></div>
+                    <div className="mono text-[11px] text-[color:var(--muted)]">{formatTime(entry.createdAt)}</div>
+                  </div>
+                  <div className="flex items-center gap-2 text-[13px] text-[color:var(--muted)]"><span className="font-medium text-[color:var(--muted-strong)]">{entry.actor}</span><span>·</span><span>{entry.detail || `${entry.entityType}:${entry.entityId}`}</span></div>
+                </ListRow>
+              )
+            })}
+          </ListFrame>
+          {visibleCount < filtered.length ? <div className="flex justify-center pt-2"><ActionButton label={`Load more (${filtered.length - visibleCount} remaining)`} onClick={() => setVisibleCount((c) => c + 100)} icon={ArrowRight} /></div> : null}
+        </>
+      )}
+    </div>
+  )
+}