Add project configuration and initial documentation files

- Introduced `archdoc.toml` configuration file for project settings, including scanning and analysis options.
- Created initial `ARCHITECTURE.md` file with project summary and structure.
- Generated documentation files for source files and modules, including placeholders for future content.
- Updated the documentation generation logic to handle new project structure and file paths.

archdoc-core/tests/golden/test_project/ARCHITECTURE.md

@@ -0,0 +1,73 @@
+# ARCHITECTURE — New Project
+
+<!-- MANUAL:BEGIN -->
+## Project summary
+**Name:** New Project
+**Description:** <FILL_MANUALLY: what this project does in 3–7 lines>
+
+## Key decisions (manual)
+- <FILL_MANUALLY>
+
+## Non-goals (manual)
+- <FILL_MANUALLY>
+<!-- MANUAL:END -->
+
+---
+
+## Document metadata
+- **Created:** 2026-01-25
+- **Updated:** 2026-01-25
+- **Generated by:** archdoc (cli) v0.1
+
+---
+
+## Rails / Tooling
+<!-- ARCHDOC:BEGIN section=rails -->
+
+No tooling information available.
+<!-- ARCHDOC:END section=rails -->
+
+---
+
+## Repository layout (top-level)
+<!-- ARCHDOC:BEGIN section=layout -->
+
+| Path | Purpose | Link |
+|------|---------|------|
+| ./src/advanced_example.py | Source file | [details](docs/architecture/files/._src_advanced_example.py.md) |
+| ./src/example.py | Source file | [details](docs/architecture/files/._src_example.py.md) |
+<!-- ARCHDOC:END section=layout -->
+
+---
+
+## Modules index
+<!-- ARCHDOC:BEGIN section=modules_index -->
+
+| Module | Symbols | Inbound | Outbound | Link |
+|--------|---------|---------|----------|------|
+| ./src/advanced_example.py | 10 | 0 | 0 | [details](docs/architecture/modules/._src_advanced_example.py.md) |
+| ./src/example.py | 5 | 0 | 0 | [details](docs/architecture/modules/._src_example.py.md) |
+<!-- ARCHDOC:END section=modules_index -->
+
+---
+
+## Critical dependency points
+<!-- ARCHDOC:BEGIN section=critical_points -->
+
+### High Fan-in (Most Called)
+| Symbol | Fan-in | Critical |
+|--------|--------|----------|
+
+### High Fan-out (Calls Many)
+| Symbol | Fan-out | Critical |
+|--------|---------|----------|
+
+### Module Cycles
+<!-- ARCHDOC:END section=critical_points -->
+
+---
+
+<!-- MANUAL:BEGIN -->
+## Change notes (manual)
+- <FILL_MANUALLY>
+<!-- MANUAL:END -->