refactor(renderer): route all Phosphor icon imports through ui/icons barrel

Create src/renderer/components/ui/icons.ts as the single re-export point
for every Phosphor icon the renderer touches, then rewrite the 95 files
that previously imported directly from "@phosphor-icons/react" to pull
from the relative-path-to-barrel instead. The TitleBar commit earlier
in this series already used ui/icons; this commit extends the pattern
to the rest of the renderer.

Benefits now wired in:
  - one location where bundle tree-shaking can be reasoned about,
  - typos like Briefcase vs BriefCase show up against a finite list,
  - re-theming or swapping icon sets is a one-file edit,
  - a lint rule that flags raw @phosphor-icons/react imports can be
    added later without mass-rewriting call sites.

The barrel also re-exports the `Icon` type so call sites that type
icon props against the Phosphor component type work unchanged.

Test count stays at 363 passing; typecheck stays at 156 errors.

src/renderer/components/social/AccountCard.tsx

@@ -1,4 +1,4 @@
-import { ShieldCheck, SignIn, Trash } from "@phosphor-icons/react";
+import { ShieldCheck, SignIn, Trash } from "../ui/icons";
 import type { SocialAccountRecord } from "@shared/types";
 import { timeAgo } from "../../lib/formatters";
 import { platformConfig } from "./social-config";

src/renderer/components/social/ActionHistory.tsx

@@ -2,7 +2,7 @@ import {
   ArrowSquareOut,
   ClockCounterClockwise,
   Robot,
-} from "@phosphor-icons/react";
+} from "../ui/icons";
 import type { BrowserActionRecord } from "@shared/types";
 import { timeAgo } from "../../lib/formatters";
 import { actionTypeLabels } from "./social-config";

src/renderer/components/social/AddAccountDialog.tsx

@@ -1,5 +1,5 @@
 import { useState } from "react";
-import { SignIn } from "@phosphor-icons/react";
+import { SignIn } from "../ui/icons";
 import type { SocialPlatform } from "@shared/types";
 import { ActionButton, Modal } from "../ui";
 import { platformConfig } from "./social-config";

src/renderer/components/social/SocialPanel.tsx

@@ -1,6 +1,6 @@
 import { useCallback, useState } from "react";
 import { AnimatePresence } from "framer-motion";
-import { Browser, Megaphone, Plus } from "@phosphor-icons/react";
+import { Browser, Megaphone, Plus } from "../ui/icons";
 import type { BrowserActionRecord, SocialAccountRecord, SocialPlatform } from "@shared/types";
 import { ActionButton } from "../ui";
 import { useT } from "../../i18n";

src/renderer/components/social/social-config.ts

@@ -25,7 +25,7 @@ import {
   Notebook,
   MusicNote,
   Lightbulb,
-} from "@phosphor-icons/react";
+} from "../ui/icons";
 import type { SocialPlatform } from "@shared/types";
 
 export const platformConfig: Record<SocialPlatform, { label: string; color: string; bgColor: string; icon: ElementType }> = {