fix: Windows path handling, light theme default, file viewer in editor, first-user admin logic

Config:
- Fixed SQLite path parsing on Windows (handle drive letters without prepending /)
- Changed default theme from dark to light
- Updated OAuth test credentials (gitea_oauth_client_id/secret)

Auth:
- First real user (excluding default admin with no password) becomes admin
- Changed user count query to exclude users without password_hash

File viewer:
- Removed separate _render_file_viewer() —

app/templates/workspace.html

@@ -14,37 +14,37 @@
 <style>
 .workspace-layout{max-width:900px;margin:0 auto;padding:32px 24px;}
 .workspace-header{margin-bottom:24px;}
-.workspace-header h1{font-size:28px;font-weight:600;margin-bottom:8px;}
-.workspace-header p{color:rgba(255,255,255,.5);font-size:14px;}
+.workspace-header h1{font-size:28px;font-weight:600;margin-bottom:8px;color:var(--text-primary);}
+.workspace-header p{color:var(--text-secondary);font-size:14px;}
 
 .forge-section{margin-bottom:32px;}
-.forge-section h2{font-size:14px;color:rgba(255,255,255,.45);text-transform:uppercase;letter-spacing:.5px;margin-bottom:12px;font-weight:500;display:flex;align-items:center;gap:8px;}
+.forge-section h2{font-size:14px;color:var(--text-dim);text-transform:uppercase;letter-spacing:.5px;margin-bottom:12px;font-weight:500;display:flex;align-items:center;gap:8px;}
 .forge-badge{display:inline-flex;align-items:center;gap:4px;padding:2px 8px;border-radius:4px;font-size:11px;font-weight:500;}
-.forge-badge.gitea{background:rgba(96,155,80,.15);color:#609b50;}
-.forge-badge.github{background:rgba(110,84,148,.15);color:#6e5494;}
-.forge-badge.builtin{background:rgba(35,131,226,.15);color:#2383E2;}
+.forge-badge.gitea{background:rgba(96,155,80,.15);color:var(--green);}
+.forge-badge.github{background:rgba(110,84,148,.15);color:var(--purple);}
+.forge-badge.builtin{background:rgba(35,131,226,.15);color:var(--accent);}
 
 .project-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:12px;}
-.project-card{background:#222;border:1px solid rgba(255,255,255,.06);border-radius:12px;padding:16px;cursor:pointer;transition:background 150ms ease;}
-.project-card:hover{background:#2A2A2A;border-color:rgba(255,255,255,.12);}
+.project-card{background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:16px;cursor:pointer;transition:background var(--transition);}
+.project-card:hover{background:var(--bg-hover);border-color:var(--border-strong);}
 .project-card-top{display:flex;align-items:flex-start;justify-content:space-between;margin-bottom:8px;}
 .project-card-icon{font-size:20px;}
-.project-card-name{font-size:14px;font-weight:500;color:#fff;margin-bottom:4px;}
-.project-card-desc{font-size:12px;color:rgba(255,255,255,.4);margin-bottom:8px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;}
-.project-card-meta{display:flex;align-items:center;gap:8px;font-size:11px;color:rgba(255,255,255,.3);}
+.project-card-name{font-size:14px;font-weight:500;color:var(--text-primary);margin-bottom:4px;}
+.project-card-desc{font-size:12px;color:var(--text-secondary);margin-bottom:8px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;}
+.project-card-meta{display:flex;align-items:center;gap:8px;font-size:11px;color:var(--text-dim);}
 
-.empty-state{text-align:center;padding:40px;color:rgba(255,255,255,.3);font-size:14px;}
-.empty-state .btn{margin-top:12px;display:inline-block;padding:8px 16px;background:#2383E2;color:#fff;border-radius:8px;text-decoration:none;font-size:13px;}
+.empty-state{text-align:center;padding:40px;color:var(--text-dim);font-size:14px;}
+.empty-state .btn{margin-top:12px;display:inline-block;padding:8px 16px;background:var(--accent);color:#fff;border-radius:var(--radius-md);text-decoration:none;font-size:13px;}
 
-.new-project-btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;background:rgba(35,131,226,.15);color:#2383E2;border:1px solid rgba(35,131,226,.3);border-radius:8px;cursor:pointer;font-size:13px;}
+.new-project-btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;background:rgba(35,131,226,.15);color:var(--accent);border:1px solid rgba(35,131,226,.3);border-radius:var(--radius-md);cursor:pointer;font-size:13px;}
 .new-project-btn:hover{background:rgba(35,131,226,.25);}
 
 /* Modal */
-.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.6);display:flex;align-items:center;justify-content:center;z-index:500;}
-.modal-box{background:#1F1F1F;border:1px solid rgba(255,255,255,.08);border-radius:18px;padding:32px;width:400px;max-width:90vw;}
-.modal-box h3{font-size:16px;margin-bottom:16px;}
-.modal-input{width:100%;padding:10px 12px;background:#2A2A2A;border:1px solid rgba(255,255,255,.1);border-radius:8px;color:#fff;font-size:14px;margin-bottom:12px;outline:none;}
-.modal-input:focus{border-color:#2383E2;}
+.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.4);display:flex;align-items:center;justify-content:center;z-index:500;}
+.modal-box{background:var(--bg-modal);border:1px solid var(--border);border-radius:var(--radius-lg);padding:32px;width:400px;max-width:90vw;box-shadow:var(--shadow-modal);}
+.modal-box h3{font-size:16px;margin-bottom:16px;color:var(--text-primary);}
+.modal-input{width:100%;padding:10px 12px;background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-md);color:var(--text-primary);font-size:14px;margin-bottom:12px;outline:none;}
+.modal-input:focus{border-color:var(--accent);}
 .modal-actions{display:flex;gap:8px;justify-content:flex-end;}
 </style>
 
@@ -72,8 +72,8 @@
           </div>
         </div>
       </template>
-      <div class="project-card" style="border:1px dashed rgba(255,255,255,.1);display:flex;align-items:center;justify-content:center;min-height:100px" @click="showCreateModal = true">
-        <span style="color:rgba(255,255,255,.3);font-size:24px">+</span>
+      <div class="project-card" style="border:1px dashed var(--border-strong);display:flex;align-items:center;justify-content:center;min-height:100px" @click="showCreateModal = true">
+        <span style="color:var(--text-dim);font-size:24px">+</span>
       </div>
     </div>
   </div>