feat: implement WebCodecs Opus decode for browser listen

- Add broadcastOpusToWeb to PcmBroadcaster interface for raw Opus packets
- Server broadcasts Opus frames with mode byte (1) + user hash + packet data
- Browser detects packet mode: mode=1 for Opus, mode=0 for legacy PCM
- Implement WebCodecs AudioDecoder for Opus decoding in browser
- Keep existing PCM playback as fallback for compatibility
- Show error if WebCodecs unsupported
- Fixes listen feature under Bun where native Opus decode unavailable

docs/superpowers/plans/2026-05-13-react-ssr-dashboard.md

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+# React SSR Dashboard Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Replace static client-rendered homepage with React server-side rendering while keeping live WebSocket/voice behavior as progressive enhancement.
+
+**Architecture:** Express `GET /` builds dashboard data, renders React component to HTML with `react-dom/server`, injects bootstrap JSON for client script. CSS/JS move to static assets; React owns initial markup only, lightweight browser JS handles tab switching, voice bridge, WebSocket updates, and async thread discovery.
+
+**Tech Stack:** React, ReactDOM server, Bun, Express, TypeScript, vanilla browser JS for progressive enhancement.
+
+---
+
+### Task 1: Add React dependencies
+
+**Files:**
+- Modify: `package.json`
+- Modify: `bun.lockb`
+
+- [ ] Run `bun add react react-dom`.
+- [ ] Run `bun add -d @types/react @types/react-dom`.
+- [ ] Verify `bun run typecheck`.
+
+### Task 2: Extract dashboard assets
+
+**Files:**
+- Create: `public/dashboard.css`
+- Create: `public/dashboard.js`
+- Modify: `public/index.html`
+
+- [ ] Move current `<style>` content to `dashboard.css`.
+- [ ] Move current `<script>` content to `dashboard.js`.
+- [ ] Keep client behavior independent from static HTML.
+
+### Task 3: Create React SSR renderer
+
+**Files:**
+- Create: `src/web/dashboardPage.tsx`
+
+- [ ] Create `DashboardPage` React component accepting: guilds, voiceChannels, watchChannels, selectedChannel, messages, status.
+- [ ] Render same Voice/Text layout as current homepage.
+- [ ] Render message cards server-side from DB metadata.
+- [ ] Export `renderDashboardPage(props)` returning full HTML with CSS/JS links and bootstrap JSON.
+
+### Task 4: Wire Express SSR route
+
+**Files:**
+- Modify: `src/webserver.ts`
+
+- [ ] Add `GET /` before static middleware fallback or before static index handling.
+- [ ] Build props from `voiceController` and `getMessagesByChannel`.
+- [ ] Respect query `?guild=<id>&channel=<id>`.
+- [ ] Render HTML with `renderDashboardPage`.
+
+### Task 5: Verify
+
+**Files:** all touched files
+
+- [ ] Run `bun run typecheck`.
+- [ ] Run `bun run test`.
+- [ ] Run short SSR import smoke if possible.