Fix: CSV importer and imported data

- pad rows, distinguish empty year, better error diagnostics
- derive year from identifier when year column is empty
- fix remaining 18 theses: Installation/Performance (slash→dash) orientation alias
- csv importer: use column-name-based header detection instead of hardcoded positions

app/migrations/applied/013_fix_remarks_keywords.php

@@ -0,0 +1,64 @@
+#!/usr/bin/env php
+<?php
+/**
+ * Migrate keywords from theses.remarks → tags + thesis_tags.
+ *
+ * The CSV importer (before the column-shift fix) stored comma-separated
+ * keywords in the `remarks` column. This script extracts them and creates
+ * proper tag rows, then clears the remarks column.
+ *
+ * Run: php migrations/pending/013_fix_remarks_keywords.php
+ */
+
+require_once __DIR__ . '/../../src/Database.php';
+
+$db = Database::getInstance();
+$pdo = $db->getPDO();
+
+// Fetch theses with non-empty remarks
+$rows = $pdo->query(
+    "SELECT id, remarks FROM theses WHERE remarks IS NOT NULL AND remarks != ''"
+)->fetchAll();
+
+$insertTag  = $pdo->prepare('INSERT OR IGNORE INTO tags (name) VALUES (?)');
+$getTagId   = $pdo->prepare('SELECT id FROM tags WHERE name = ?');
+$insertLink = $pdo->prepare('INSERT OR IGNORE INTO thesis_tags (thesis_id, tag_id) VALUES (?, ?)');
+$clearRemarks = $pdo->prepare('UPDATE theses SET remarks = NULL WHERE id = ?');
+
+$pdo->beginTransaction();
+
+try {
+    $migrated = 0;
+    foreach ($rows as $row) {
+        $thesisId = (int)$row['id'];
+        $raw      = trim($row['remarks']);
+        if ($raw === '') {
+            $clearRemarks->execute([$thesisId]);
+            continue;
+        }
+
+        $keywords = array_map('trim', explode(',', $raw));
+        foreach ($keywords as $kw) {
+            $kw = trim($kw);
+            if ($kw === '' || mb_strlen($kw) > 100) continue;
+
+            // Create tag if needed
+            $insertTag->execute([$kw]);
+            $getTagId->execute([$kw]);
+            $tagId = $getTagId->fetchColumn();
+            if ($tagId) {
+                $insertLink->execute([$thesisId, (int)$tagId]);
+            }
+        }
+
+        $clearRemarks->execute([$thesisId]);
+        $migrated++;
+    }
+
+    $pdo->commit();
+    echo "Done. Migrated keywords for $migrated theses.\n";
+} catch (Throwable $e) {
+    $pdo->rollBack();
+    echo "Error: " . $e->getMessage() . "\n";
+    exit(1);
+}