Improve sessions table migration and structure checks

Enhances the database migration script to verify and update the sessions table structure. The script now checks for the correct primary key, adds the last_activity column if missing, and recreates the table if the structure is outdated, ensuring consistency and referential integrity.

install-improved.sh

@@ -343,17 +343,51 @@ run_database_migration() {
         print_info "Creating sessions table..."
         sqlite3 "$DB_PATH" "
             CREATE TABLE IF NOT EXISTS sessions (
-                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                token VARCHAR(64) PRIMARY KEY,
                 user_id INTEGER NOT NULL,
-                token TEXT UNIQUE NOT NULL,
-                created_at TEXT DEFAULT CURRENT_TIMESTAMP,
-                expires_at TEXT NOT NULL,
-                FOREIGN KEY (user_id) REFERENCES users(id)
+                created_at DATETIME NOT NULL,
+                expires_at DATETIME NOT NULL,
+                last_activity DATETIME NOT NULL,
+                FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
             );
         "
         print_success "Created sessions table"
     else
-        print_success "Sessions table already exists"
+        print_info "Checking sessions table structure..."
+        
+        # Check if sessions table has the correct structure (token as PRIMARY KEY)
+        local sessions_has_token_pk=$(sqlite3 "$DB_PATH" "PRAGMA table_info(sessions);" | grep -E "^0\|token\|" || echo "")
+        local sessions_has_last_activity=$(sqlite3 "$DB_PATH" "PRAGMA table_info(sessions);" | grep "last_activity" || echo "")
+        
+        # If table has old structure (id as PRIMARY KEY instead of token), recreate it
+        if [ -z "$sessions_has_token_pk" ]; then
+            print_warning "Sessions table has old structure - recreating..."
+            
+            # Drop old sessions (they will be invalid anyway after structure change)
+            sqlite3 "$DB_PATH" "DROP TABLE IF EXISTS sessions;"
+            
+            # Create with correct structure
+            sqlite3 "$DB_PATH" "
+                CREATE TABLE sessions (
+                    token VARCHAR(64) PRIMARY KEY,
+                    user_id INTEGER NOT NULL,
+                    created_at DATETIME NOT NULL,
+                    expires_at DATETIME NOT NULL,
+                    last_activity DATETIME NOT NULL,
+                    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+                );
+            "
+            print_success "Recreated sessions table with correct structure"
+        elif [ -z "$sessions_has_last_activity" ]; then
+            # Table exists with correct structure but missing last_activity column
+            print_info "Adding last_activity column to sessions table..."
+            sqlite3 "$DB_PATH" "ALTER TABLE sessions ADD COLUMN last_activity DATETIME;"
+            # Set default value for existing rows
+            sqlite3 "$DB_PATH" "UPDATE sessions SET last_activity = created_at WHERE last_activity IS NULL;"
+            print_success "Added last_activity column"
+        else
+            print_success "Sessions table structure is correct"
+        fi
     fi
     
     # Check if audit_log table exists