Build: Web UI + mDNS (pedal.local)

FastAPI web server with REST + WebSocket, 5 Jinja2 HTML pages,
mobile-friendly dark theme CSS, page-specific JS controllers,
and Avahi mDNS service advertisement for pedal.local.

Files:
  src/web/server.py          — FastAPI app with 17 REST endpoints + /ws WebSocket
  src/web/__init__.py         — Package init with WebServer, WebServerDeps exports
  src/web/templates/*.html    — Dashboard, Presets, Models, IRs, Settings (base)
  src/web/static/style.css    — Dark mobile-first CSS (80-82% max-width)
  src/web/static/websocket.js — Auto-reconnecting WebSocket manager
  src/web/static/app.js       — Dashboard live updates + REST helpers
  src/web/static/presets.js   — Bank/preset CRUD modal UI
  src/web/static/models.js    — NAM model list/load/upload
  src/web/static/irs.js       — IR file list/load/upload
  etc/avahi/pi-multifx-pedal.service — Avahi service advertisement
  scripts/setup-mdns.sh       — One-shot mDNS setup (avahi, hostname, restart)
  main.py                     — Wire WebServer into boot/shutdown
  requirements.txt            — Add fastapi, uvicorn, jinja2, python-multipart
  tests/test_web.py           — 36 tests (pages, REST, WebSocket, errors)

All 36 tests pass.

src/web/templates/settings.html

@@ -0,0 +1,68 @@
+{% extends "base.html" %}
+{% block title %}Settings — Pi Multi-FX Pedal{% endblock %}
+{% block content %}
+<div class="page settings-page">
+    <div class="page-header">
+        <h1>Settings</h1>
+    </div>
+
+    <div class="card">
+        <div class="card-header">
+            <h2>Connection</h2>
+        </div>
+        <div class="card-body">
+            <div class="setting-row">
+                <div class="setting-label">Hostname</div>
+                <div class="setting-value"><code id="hostname">pedal.local</code></div>
+            </div>
+            <div class="setting-row">
+                <div class="setting-label">Web Server</div>
+                <div class="setting-value"><code id="web-url">http://pedal.local:8080</code></div>
+            </div>
+            <div class="setting-row">
+                <div class="setting-label">Connected Clients</div>
+                <div class="setting-value"><span id="ws-count">0</span></div>
+            </div>
+        </div>
+    </div>
+
+    <div class="card">
+        <div class="card-header">
+            <h2>Audio</h2>
+        </div>
+        <div class="card-body">
+            <div class="setting-row">
+                <div class="setting-label">Master Volume</div>
+                <div class="setting-value">
+                    <input type="range" class="slider" id="settings-volume"
+                           min="0" max="100" value="{{ (master_volume * 100)|int }}"
+                           oninput="setVolume(this.value)">
+                    <span id="settings-volume-text">{{ (master_volume * 100)|int }}%</span>
+                </div>
+            </div>
+            <div class="setting-row">
+                <div class="setting-label">Tuner</div>
+                <div class="setting-value">
+                    <button class="btn toggle-btn {% if tuner_enabled %}active{% endif %}"
+                            id="settings-tuner-btn" onclick="toggleTuner()">
+                        {% if tuner_enabled %}ON{% else %}OFF{% endif %}
+                    </button>
+                </div>
+            </div>
+        </div>
+    </div>
+
+    <div class="card">
+        <div class="card-header">
+            <h2>About</h2>
+        </div>
+        <div class="card-body">
+            <div class="about-info">
+                <p><strong>Pi Multi-FX Pedal</strong> v0.1.0</p>
+                <p>Raspberry Pi 4B — Python 3.11 — JACK Audio</p>
+                <p><a href="https://gitea.ourpad.casa/shawn/pi-multifx-pedal" target="_blank">Gitea Repository</a></p>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}