Restructure repository and implement secure search feature

Phase 1: Consolidate shared infrastructure
- Create shared/ directory for common code
- Consolidate Database.php from front-backend and formulaire into unified shared/Database.php
  - Smart path detection for test.db vs posterg.db
  - Secure search with wildcard escaping and input validation
  - Support both singleton and direct instantiation patterns
  - Full CRUD methods for admin functionality
- Move RateLimit.php to shared/ (30 requests/min)
- Update all require paths across apps to use shared/

Phase 2: Reorganize directory structure
- Rename front-backend/ → apps/public/
- Rename formulaire/ → apps/admin/
- Rename db/ → database/
- Update all file paths for new structure
- Create root .gitignore excluding databases, cache, logs

Implement secure search feature
- Add apps/public/search.php with full-text search across theses
- Search filters: query, year, orientation, AP program, keywords
- Security features:
  - SQL injection prevention (prepared statements)
  - Wildcard injection prevention (escape % and _)
  - Input validation (max 200 chars, year range 1900-2100)
  - Rate limiting (30 req/min per IP)
  - Pagination limited to 100 results/page
  - XSS protection (htmlspecialchars on output)

Add comprehensive test suite
- Create apps/public/tests/ with proper structure
  - tests/Integration/SearchTest.php - 12 search scenarios
  - tests/Security/SecurityTest.php - vulnerability testing
  - tests/Unit/RateLimitTest.php - rate limit behavior
- Create database/fixtures/CreateTestDatabase.php
- Add apps/public/run-tests.php test runner
- All tests passing (4/4 suites)

Update deployment configuration
- Rename justfile 'sync' recipe to 'deploy'
- Create deploy group with separate deploy-public and deploy-admin
- Add test-deploy recipe for test database
- Exclude *.db, tests/, cache/, *.md from production deploy
- Deploy shared/ to both public and admin locations

Stats: +4482 insertions, -654 deletions across 72 files

apps/public/contact.php

@@ -0,0 +1,19 @@
+<?php include 'inc/header.php'; ?>
+<section class="section">
+  <div class="container">
+    <h2 class="title is-2">Contact</h2>
+    <div class="content">
+
+      <p>Laurent Leprince, <br>
+        Bibliothèque d'architecture, d'ingénierie architecturale, d'urbanisme (BAIU) :<br>
+        laurent.leprince@uclouvain.be</p>
+
+      <p>Xavier Gorgol, <br>
+        Responsable des mémoires de l'ERG :<br>
+        xavier.gorgol@erg.be<br></p>
+
+      <p>Brigitte Ledune,<br>
+        Cours de suivi de mémoire : <br>
+        brigitte.ledune@erg.be</p>
+
+      <?php include 'inc/footer.php'; ?>