feat(design): surface phase PR 1 — Lucide icon migration + scale enforcement

Replaces every hand-inlined SVG in the chrome (60 across 15 files)
with Lucide components. Snaps icon sizes to the doc's 16/24 scale —
all icons in this pass land at 16. AppLogo wordmark stays as the
legitimate "custom app icon" exception per the doc; GraphView's <svg>
mount point for D3 stays as well.

Replaces emoji-as-icons in clear button-affordance cases with their
Lucide equivalents: ✕ → X (close/dismiss buttons across 8 files), ✓ →
Check (ProjectView task-advance button), 🎤 → Mic (ChatPanel voice
CTA), 📎 → Paperclip (ChatView context toggle), &uarr; → ArrowUp
(ChatInputBar Send), &times; → X (ChatPanel context-note remove), ☀/☾
→ Sun/Moon (AppHeader theme toggle).

Inline emoji punctuation in textual confirmation copy ("Saved ✓",
"Created ✓", `done: "✓"` status maps, `'✓' : '📄'` interpolations)
is left for surface-phase voice/tone touchups — replacing requires
structural template changes and is best done per-component.

Stroke weight stays at Lucide's default 2px; tightening to the doc's
1.5/1 is deferred per the surface-phase spec (option ii: drop-in +
scale enforcement).

Adds lucide-vue-next ^0.469.0 to frontend/package.json. Docker
rebuild handles the install.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/components/MarkdownToolbar.vue

@@ -1,24 +1,40 @@
 <script setup lang="ts">
 import type { Editor } from "@tiptap/vue-3";
+import {
+  Bold,
+  Italic,
+  Strikethrough,
+  Heading1,
+  Heading2,
+  Heading3,
+  List,
+  ListOrdered,
+  ListChecks,
+  Code,
+  SquareCode,
+  Quote,
+  Link as LinkIcon,
+  Brackets,
+} from "lucide-vue-next";
+import type { Component } from "vue";
 
 const props = defineProps<{ editor: Editor | null }>();
 
-// SVG icons — Material Design paths (24x24) or custom SVG
-const ICONS: Record<string, string> = {
-  bold: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M15.6 10.79c.97-.67 1.65-1.77 1.65-2.79 0-2.26-1.75-4-4-4H7v14h7.04c2.09 0 3.71-1.7 3.71-3.79 0-1.52-.86-2.82-2.15-3.42zM10 6.5h3c.83 0 1.5.67 1.5 1.5s-.67 1.5-1.5 1.5h-3v-3zm3.5 9H10v-3h3.5c.83 0 1.5.67 1.5 1.5s-.67 1.5-1.5 1.5z"/></svg>`,
-  italic: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M10 4v3h2.21l-3.42 8H6v3h8v-3h-2.21l3.42-8H18V4z"/></svg>`,
-  strike: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M10 19h4v-3h-4v3zM5 4v3h5v3h4V7h5V4H5zM3 14h18v-2H3v2z"/></svg>`,
-  h1: `<svg viewBox="0 0 24 24" width="15" height="15"><text x="1" y="17" font-family="sans-serif" font-weight="800" font-size="16" fill="currentColor">H</text><text x="14" y="17" font-family="sans-serif" font-weight="700" font-size="11" fill="currentColor">1</text></svg>`,
-  h2: `<svg viewBox="0 0 24 24" width="15" height="15"><text x="1" y="17" font-family="sans-serif" font-weight="800" font-size="16" fill="currentColor">H</text><text x="14" y="17" font-family="sans-serif" font-weight="700" font-size="11" fill="currentColor">2</text></svg>`,
-  h3: `<svg viewBox="0 0 24 24" width="15" height="15"><text x="1" y="17" font-family="sans-serif" font-weight="800" font-size="16" fill="currentColor">H</text><text x="14" y="17" font-family="sans-serif" font-weight="700" font-size="11" fill="currentColor">3</text></svg>`,
-  ul: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M4 10.5c-.83 0-1.5.67-1.5 1.5s.67 1.5 1.5 1.5 1.5-.67 1.5-1.5-.67-1.5-1.5-1.5zm0-6c-.83 0-1.5.67-1.5 1.5S3.17 7.5 4 7.5 5.5 6.83 5.5 6 4.83 4.5 4 4.5zm0 12c-.83 0-1.5.68-1.5 1.5s.68 1.5 1.5 1.5 1.5-.68 1.5-1.5-.67-1.5-1.5-1.5zM7 19h14v-2H7v2zm0-6h14v-2H7v2zm0-8v2h14V5H7z"/></svg>`,
-  ol: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M2 17h2v.5H3v1h1v.5H2v1h3v-4H2zm1-9h1V4H2v1h1zm-1 3h1.8L2 13.1v.9h3v-1H3.2L5 10.9V10H2zm5-3h13V6H7v2zm0 4h13v-2H7v2zm0 4h13v-2H7v2z"/></svg>`,
-  task: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M19 3H5c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h14c1.1 0 2-.9 2-2V5c0-1.1-.9-2-2-2zm-9 14l-5-5 1.41-1.41L10 14.17l7.59-7.59L19 8l-9 9z"/></svg>`,
-  code: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M9.4 16.6L4.8 12l4.6-4.6L8 6l-6 6 6 6 1.4-1.4zm5.2 0l4.6-4.6-4.6-4.6L16 6l6 6-6 6-1.4-1.4z"/></svg>`,
-  codeblock: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M20 3H4v10c0 2.21 1.79 4 4 4h6c2.21 0 4-1.79 4-4v-3h2c1.11 0 2-.89 2-2V5c0-1.11-.89-2-2-2zm0 5h-2V5h2v3zM4 19h16v2H4z"/></svg>`,
-  quote: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M6 17h3l2-4V7H5v6h3zm8 0h3l2-4V7h-6v6h3z"/></svg>`,
-  link: `<svg viewBox="0 0 24 24" width="15" height="15" fill="currentColor"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7c-2.76 0-5 2.24-5 5s2.24 5 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1zM8 13h8v-2H8v2zm9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1s-1.39 3.1-3.1 3.1h-4V17h4c2.76 0 5-2.24 5-5s-2.24-5-5-5z"/></svg>`,
-  wikilink: `<svg viewBox="0 0 24 24" width="15" height="15" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M8 3H5a2 2 0 0 0-2 2v14a2 2 0 0 0 2 2h3"/><path d="M16 3h3a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2h-3"/></svg>`,
+const ICONS: Record<string, Component> = {
+  bold: Bold,
+  italic: Italic,
+  strike: Strikethrough,
+  h1: Heading1,
+  h2: Heading2,
+  h3: Heading3,
+  ul: List,
+  ol: ListOrdered,
+  task: ListChecks,
+  code: Code,
+  codeblock: SquareCode,
+  quote: Quote,
+  link: LinkIcon,
+  wikilink: Brackets,
 };
 
 const groups = [
@@ -81,7 +97,7 @@ const groups = [
           tabindex="-1"
           @mousedown.prevent="btn.command()"
         >
-          <span class="btn-icon" v-html="ICONS[btn.id]" />
+          <component :is="ICONS[btn.id]" class="btn-icon" :size="16" />
         </button>
       </div>
       <span v-if="gi < groups.length - 1" class="toolbar-sep" aria-hidden="true" />