test(bf-2y7uh): create forms_integration test module scaffold

- Created tests/forms_integration.rs with basic test module structure
- Created tests/mod.rs to aggregate test modules
- Added module documentation for forms integration tests
- File compiles successfully with cargo test --test forms_integration

Acceptance criteria:
- tests/forms_integration.rs exists ✓
- tests/mod.rs includes the module declaration ✓
- cargo test --test forms_integration compiles ✓
- File has basic test module skeleton ✓

Closes bf-2y7uh

tests/forms_integration.rs

@@ -0,0 +1,14 @@
+//! Forms integration tests.
+//!
+//! This test module verifies PDF form handling including:
+//! - AcroForm detection and parsing
+//! - Form field extraction and validation
+//! - Widget annotation processing
+//! - Form data encoding/decoding
+
+// Placeholder module - tests will be added in subsequent beads
+
+#[cfg(test)]
+mod tests {
+    // Test functions will be added here
+}

tests/mod.rs

@@ -0,0 +1,5 @@
+//! Test module aggregation.
+//!
+//! This file organizes integration test modules.
+
+mod forms_integration;