Implement security hardening across frontend, backend, and infrastructure

- nginx: add X-Content-Type-Options, X-Frame-Options, X-XSS-Protection,
  and Referrer-Policy headers on all responses; rate limit /api/auth/login
  to 5 req/min per IP (burst 3) to prevent brute force
- frontend: add escHtml() utility to api.js; use it on all notes fields
  across dashboard, log, history, flock, and budget pages to prevent XSS
- log.js: fix broken loadRecent() call referencing removed #recent-body
  element; replaced with loadHistory() from history.js
- schemas.py: raise minimum password length from 6 to 10 characters
- admin.py: add audit logging for password reset, disable, delete, and
  impersonate actions; fix impersonate to use named admin param for logging
- main.py: add startup env validation — exits with clear error if any
  required env var is missing; configure structured logging to stdout
- docker-compose.yml: add log rotation (10 MB / 3 files) to all services

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nginx/html/js/log.js

@@ -1,26 +1,3 @@
-async function loadRecent() {
-    const tbody = document.getElementById('recent-body');
-    try {
-        const eggs = await API.get('/api/eggs');
-        const recent = eggs.slice(0, 7);
-
-        if (recent.length === 0) {
-            tbody.innerHTML = '<tr class="empty-row"><td colspan="3">No entries yet.</td></tr>';
-            return;
-        }
-
-        tbody.innerHTML = recent.map(e => `
-            <tr>
-                <td>${fmtDate(e.date)}</td>
-                <td>${e.eggs}</td>
-                <td class="notes">${e.notes || ''}</td>
-            </tr>
-        `).join('');
-    } catch (err) {
-        tbody.innerHTML = '<tr class="empty-row"><td colspan="3">Could not load recent entries.</td></tr>';
-    }
-}
-
 document.addEventListener('DOMContentLoaded', () => {
     const form = document.getElementById('log-form');
     const msg  = document.getElementById('msg');
@@ -42,11 +19,9 @@ document.addEventListener('DOMContentLoaded', () => {
             showMessage(msg, 'Entry saved!');
             form.reset();
             setToday(document.getElementById('date'));
-            loadRecent();
+            loadHistory();
         } catch (err) {
             showMessage(msg, `Error: ${err.message}`, 'error');
         }
     });
-
-    loadRecent();
 });