refactor: Modularize server into separate concerns

Split monolithic index.ts (~1400 lines) into modular structure:
- config.ts: Server configuration and constants
- db/: Database initialization, migrations, and seeds
- routes/: API handlers by domain (themes, canvas, components, etc.)
- services/: Terminal WebSocket server
- utils/: CORS helpers

Entry point now only coordinates initialization.

server/routes/index.ts

@@ -0,0 +1,172 @@
+import { optionsResponse, notFoundResponse } from '../utils/cors'
+import { handleHistory } from './history'
+import { handleConfig, handleHealth } from './config'
+import { handleWebMCPToken } from './webmcp'
+import { handleComponents, handleComponentById, handleComponentUsage } from './components'
+import { handleThemes, handleActiveTheme, handleDesignTokens, handleThemeById, handleThemeExport } from './themes'
+import { handleCanvas, handleCanvasById, handleToolbarCanvas, handleDefaultCanvas, handleCanvasComponents, handleCanvasComponentById } from './canvas'
+import { handleGiteaRepo, handleGiteaTree, handleGiteaFile } from './gitea'
+import { handleTables, handleStats, handleTableSchema, handleTableData, handleQuery } from './database'
+
+export async function handleRequest(req: Request): Promise<Response> {
+  const url = new URL(req.url)
+  const path = url.pathname
+
+  // CORS preflight
+  if (req.method === 'OPTIONS') {
+    return optionsResponse()
+  }
+
+  // Health
+  if (path === '/api/health') {
+    return handleHealth()
+  }
+
+  // History
+  if (path === '/api/history') {
+    const res = await handleHistory(req, url)
+    if (res) return res
+  }
+
+  // Config
+  if (path === '/api/config') {
+    const res = await handleConfig(req, url)
+    if (res) return res
+  }
+
+  // WebMCP Token
+  if (path === '/api/webmcp-token') {
+    const res = await handleWebMCPToken(req)
+    if (res) return res
+  }
+
+  // Components
+  if (path === '/api/components') {
+    const res = await handleComponents(req)
+    if (res) return res
+  }
+
+  // Component usage
+  const componentUsageMatch = path.match(/^\/api\/components\/([^/]+)\/usage$/)
+  if (componentUsageMatch && req.method === 'GET') {
+    return handleComponentUsage(componentUsageMatch[1])
+  }
+
+  // Component by ID
+  if (path.startsWith('/api/components/') && !path.includes('/usage')) {
+    const id = path.split('/').pop()!
+    const res = await handleComponentById(req, id)
+    if (res) return res
+  }
+
+  // Themes
+  if (path === '/api/themes') {
+    const res = await handleThemes(req)
+    if (res) return res
+  }
+
+  if (path === '/api/themes/active') {
+    return handleActiveTheme()
+  }
+
+  if (path === '/api/design-tokens') {
+    return handleDesignTokens()
+  }
+
+  // Theme export
+  if (path.startsWith('/api/themes/export/')) {
+    const id = path.split('/').pop()!
+    if (req.method === 'GET') {
+      return handleThemeExport(id)
+    }
+  }
+
+  // Theme by ID
+  if (path.startsWith('/api/themes/') && !path.includes('/active') && !path.includes('/export')) {
+    const pathParts = path.split('/')
+    const id = pathParts[3]
+    const action = pathParts[4]
+    const res = await handleThemeById(req, id, action)
+    if (res) return res
+  }
+
+  // Canvas toolbar
+  if (path === '/api/canvas/toolbar') {
+    return handleToolbarCanvas()
+  }
+
+  // Canvas default
+  if (path === '/api/canvas/default') {
+    return handleDefaultCanvas()
+  }
+
+  // Canvas list/create
+  if (path === '/api/canvas') {
+    const res = await handleCanvas(req)
+    if (res) return res
+  }
+
+  // Canvas components
+  const canvasComponentsMatch = path.match(/^\/api\/canvas\/([^/]+)\/components\/?$/)
+  if (canvasComponentsMatch) {
+    const res = await handleCanvasComponents(req, canvasComponentsMatch[1])
+    if (res) return res
+  }
+
+  // Canvas component by ID
+  const canvasComponentMatch = path.match(/^\/api\/canvas\/([^/]+)\/components\/([^/]+)$/)
+  if (canvasComponentMatch) {
+    const res = await handleCanvasComponentById(req, canvasComponentMatch[1], canvasComponentMatch[2])
+    if (res) return res
+  }
+
+  // Canvas by ID
+  if (path.startsWith('/api/canvas/') && !path.includes('/components')) {
+    const pathParts = path.split('/')
+    const id = pathParts[3]
+    const action = pathParts[4]
+    const res = await handleCanvasById(req, id, action)
+    if (res) return res
+  }
+
+  // Gitea
+  if (path === '/api/gitea/repo' && req.method === 'POST') {
+    return handleGiteaRepo(req)
+  }
+
+  if (path === '/api/gitea/tree' && req.method === 'POST') {
+    return handleGiteaTree(req)
+  }
+
+  if (path === '/api/gitea/file' && req.method === 'POST') {
+    return handleGiteaFile(req)
+  }
+
+  // Database Explorer
+  if (path === '/api/database/tables') {
+    return handleTables()
+  }
+
+  if (path === '/api/database/stats') {
+    return handleStats()
+  }
+
+  // Table schema
+  const tableSchemaMatch = path.match(/^\/api\/database\/tables\/([^/]+)\/schema$/)
+  if (tableSchemaMatch && req.method === 'GET') {
+    return handleTableSchema(decodeURIComponent(tableSchemaMatch[1]))
+  }
+
+  // Table data
+  const tableDataMatch = path.match(/^\/api\/database\/tables\/([^/]+)\/data$/)
+  if (tableDataMatch && req.method === 'GET') {
+    return handleTableData(decodeURIComponent(tableDataMatch[1]), url)
+  }
+
+  // Database query
+  if (path === '/api/database/query' && req.method === 'POST') {
+    return handleQuery(req)
+  }
+
+  return notFoundResponse()
+}