feat: Add source code viewer with Gitea integration

- Add /source page with file explorer and code viewer
- Connect to Gitea API for repository browsing
- Implement MCP tools: get_repo_info, list_repo_files, read_repo_file, search_repo_code
- Default to nucleo000/agent-ui repository
- Support branch switching and file search

server/index.ts

@@ -861,6 +861,142 @@ Bun.serve({
       }, { headers: corsHeaders })
     }
 
+    // =====================
+    // API de Gitea (Source Code Viewer)
+    // =====================
+
+    // POST /api/gitea/repo - Connect and get repo info
+    if (url.pathname === '/api/gitea/repo' && req.method === 'POST') {
+      const body = await req.json()
+      const { giteaUrl, username, password, owner, repo } = body
+
+      if (!giteaUrl || !username || !password || !owner || !repo) {
+        return Response.json({ error: 'Missing required fields' }, { status: 400, headers: corsHeaders })
+      }
+
+      try {
+        const auth = Buffer.from(`${username}:${password}`).toString('base64')
+
+        // Get repo info
+        const repoRes = await fetch(`${giteaUrl}/api/v1/repos/${owner}/${repo}`, {
+          headers: { 'Authorization': `Basic ${auth}` }
+        })
+
+        if (!repoRes.ok) {
+          if (repoRes.status === 401) {
+            return Response.json({ error: 'Invalid credentials' }, { status: 401, headers: corsHeaders })
+          }
+          if (repoRes.status === 404) {
+            return Response.json({ error: 'Repository not found' }, { status: 404, headers: corsHeaders })
+          }
+          throw new Error('Failed to connect to Gitea')
+        }
+
+        const repoData = await repoRes.json()
+
+        // Get branches
+        const branchesRes = await fetch(`${giteaUrl}/api/v1/repos/${owner}/${repo}/branches`, {
+          headers: { 'Authorization': `Basic ${auth}` }
+        })
+
+        let branches = ['main']
+        if (branchesRes.ok) {
+          const branchesData = await branchesRes.json()
+          branches = branchesData.map((b: any) => b.name)
+        }
+
+        return Response.json({
+          repo: {
+            name: repoData.name,
+            description: repoData.description,
+            default_branch: repoData.default_branch,
+            stars_count: repoData.stars_count,
+            forks_count: repoData.forks_count,
+            owner: { login: repoData.owner?.login || owner }
+          },
+          branches
+        }, { headers: corsHeaders })
+      } catch (e: any) {
+        return Response.json({ error: e.message }, { status: 500, headers: corsHeaders })
+      }
+    }
+
+    // POST /api/gitea/tree - Get file tree
+    if (url.pathname === '/api/gitea/tree' && req.method === 'POST') {
+      const body = await req.json()
+      const { giteaUrl, username, password, owner, repo, branch, path } = body
+
+      try {
+        const auth = Buffer.from(`${username}:${password}`).toString('base64')
+        const apiPath = path ? `${giteaUrl}/api/v1/repos/${owner}/${repo}/contents/${path}?ref=${branch}`
+                             : `${giteaUrl}/api/v1/repos/${owner}/${repo}/contents?ref=${branch}`
+
+        const res = await fetch(apiPath, {
+          headers: { 'Authorization': `Basic ${auth}` }
+        })
+
+        if (!res.ok) {
+          throw new Error('Failed to load tree')
+        }
+
+        const data = await res.json()
+        const items = Array.isArray(data) ? data : [data]
+
+        const tree = items
+          .map((item: any) => ({
+            name: item.name,
+            path: item.path,
+            type: item.type === 'dir' ? 'dir' : 'file',
+            children: item.type === 'dir' ? [] : undefined
+          }))
+          .sort((a: any, b: any) => {
+            // Folders first, then files
+            if (a.type !== b.type) return a.type === 'dir' ? -1 : 1
+            return a.name.localeCompare(b.name)
+          })
+
+        return Response.json({ tree }, { headers: corsHeaders })
+      } catch (e: any) {
+        return Response.json({ error: e.message }, { status: 500, headers: corsHeaders })
+      }
+    }
+
+    // POST /api/gitea/file - Get file content
+    if (url.pathname === '/api/gitea/file' && req.method === 'POST') {
+      const body = await req.json()
+      const { giteaUrl, username, password, owner, repo, branch, path } = body
+
+      try {
+        const auth = Buffer.from(`${username}:${password}`).toString('base64')
+
+        const res = await fetch(
+          `${giteaUrl}/api/v1/repos/${owner}/${repo}/contents/${path}?ref=${branch}`,
+          { headers: { 'Authorization': `Basic ${auth}` } }
+        )
+
+        if (!res.ok) {
+          throw new Error('Failed to load file')
+        }
+
+        const data = await res.json()
+
+        // Decode base64 content
+        let content = ''
+        if (data.content) {
+          content = Buffer.from(data.content, 'base64').toString('utf-8')
+        }
+
+        return Response.json({
+          content,
+          encoding: data.encoding,
+          size: data.size,
+          sha: data.sha
+        }, { headers: corsHeaders })
+      } catch (e: any) {
+        return Response.json({ error: e.message }, { status: 500, headers: corsHeaders })
+      }
+    }
+
     // =====================
     // API de Database Explorer
     // =====================