docs: restructure architecture documentation and add new guides

docs/architecture/storage/filesystem.md

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+<div align="center">
+  <h1>Filesystem Architecture</h1>
+  <p><em>Virtual File System layer and FAT32 abstraction in BoredOS.</em></p>
+</div>
+
+---
+
+BoredOS implements a rudimentary but functional filesystem layer designed to support reading system assets and user applications during runtime.
+
+## Virtual File System (VFS)
+
+The Virtual File System acts as an abstraction layer across different underlying storage mechanisms (even if, currently, only one type is fully utilized). System calls targeting files (`SYS_FS`) route through the VFS rather than interacting with the disk directly.
+
+Key VFS functionalities include:
+-   **File Descriptors**: Mapping integer IDs to internal file structures for userland processes.
+-   **Standard Operations**: Standardizing `open()`, `read()`, `write()`, `close()`, `seek()`, and directory listings.
+-   **Path Parsing**: Resolving absolute and relative paths.
+-   **SMP Safety**: All VFS and underlying FAT32 operations are protected by a global **Spinlock**. This ensures that multiple cores can safely read from the filesystem simultaneously without corrupting internal file seek pointers or directory cache states.
+
+## FAT32 Implementation
+
+The primary filesystem logic in `fat32.c` handles both in-memory RAM-based filesystem simulation and physical ATA block devices.
+
+### Storage Support
+
+BoredOS supports two main types of storage for its FAT32 implementation:
+
+1.  **RAMFS (Boot Modules)**: During boot, Limine loads necessary files (such as userland `.elf` binaries, fonts, and wallpapers) into memory as standard boot modules. The FAT32 code parses these loaded memory modules and automatically constructs a synthetic FAT32 directory tree inside RAM (mounted as `A:`).
+2.  **ATA Drives**: The kernel includes a basic PIO-based ATA driver that can detect and read/write to physical IDE/PATA hard disks.
+    -   **GPT is NOT supported**: Currently, only **MBR (Master Boot Record)** partition tables or **raw (partitionless)** disks are supported.
+    -   **Filesystem**: The partition must be formatted as **FAT32**.
+
+### Auto-detection
+The `Disk Manager` automatically probes primary and secondary IDE channels during initialization. If a valid FAT32 partition is found (either directly at sector 0 or via an MBR partition table), the disk is assigned a drive letter (starting from `B:`) and becomes accessible to the VFS.
+
+
+---