Documentation: Architecture: Fill out architecture documents.

Add comprehensive architecture documentation including:
- System overview with layered architecture description
- Detailed component responsibilities and data flows
- Key architectural patterns and integration points
- Product requirements with functional requirements and user stories
- Enhanced filesystem documentation with module responsibilities

The documentation covers the factory, decorator, behavior, standard, and
utility layers, along with class creation and attribute access flows. Also
documents extension points, dependencies, and architectural goals.

Co-Authored-By: Claude (Sonnet 4.5) <noreply@anthropic.com>

Author: claude

documentation/architecture/filesystem.rst

@@ -57,22 +57,181 @@ The main Python package follows the standard ``sources/`` directory pattern:
 .. code-block::
 
     sources/
-    ├── classcore/          # Main Python package
-    │   ├── __/                      # Centralized import hub
-    │   │   ├── __init__.py          # Re-exports core utilities
-    │   │   ├── imports.py           # External library imports
-    │   │   └── nomina.py            # python-classcore-specific naming constants
-    │   ├── __init__.py              # Package entry point
-    │   ├── py.typed                 # Type checking marker
-    │   └── [modules].py             # Feature-specific modules
-    
+    └── classcore/                   # Main Python package
+        ├── __/                      # Centralized import hub
+        │   ├── __init__.py          # Re-exports core utilities
+        │   ├── imports.py           # External library imports
+        │   ├── nomina.py            # Naming constants
+        │   └── doctab.py            # Documentation table fragments
+        ├── __init__.py              # Package entry point
+        ├── py.typed                 # Type checking marker
+        ├── decorators.py            # Class decorator utilities
+        ├── exceptions.py            # Package exception classes
+        ├── factories.py             # Metaclass factory functions
+        ├── nomina.py                # Public naming types and utilities
+        ├── utilities.py             # Class manipulation utilities
+        └── standard/                # Standard behaviors subpackage
+            ├── __.py                # Inherits parent imports
+            ├── __init__.py          # Subpackage entry point
+            ├── behaviors.py         # Immutability and concealment logic
+            ├── classes.py           # Standard metaclasses and base classes
+            ├── decorators.py        # Standard class decorators
+            ├── dynadoc.py           # Documentation configuration
+            ├── modules.py           # Module reclassification utilities
+            └── nomina.py            # Standard-specific naming types
+
+Module Responsibilities
+-------------------------------------------------------------------------------
+
+Core Package (``sources/classcore/``)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+``__/__init__.py``
+    Re-exports commonly used imports from ``imports.py`` for convenient access
+    via ``from . import __`` in all package modules.
+
+``__/imports.py``
+    Centralizes all external library imports. Provides abbreviated aliases for
+    frequently used types and modules (e.g., ``cabc`` for
+    ``collections.abc``, ``typx`` for ``typing``).
+
+``__/nomina.py``
+    Package-specific naming constants and utilities used internally by the
+    ``__`` import hub.
+
+``__/doctab.py``
+    Documentation table with reusable fragments for dynadoc interpolation.
+
+``__init__.py``
+    Package entry point. Exports public API, applies standard behaviors to
+    package module, sets version.
+
+``decorators.py``
+    Class decorator utilities:
+
+    - ``apply_decorators``: Apply decorator sequences with class replacement
+      handling
+    - ``decoration_by``: Compose multiple decorators
+    - ``produce_class_construction_decorator``: Create metaclass ``__new__``
+      decorators
+    - ``produce_class_initialization_decorator``: Create metaclass ``__init__``
+      decorators
+
+``exceptions.py``
+    Package exception hierarchy. All exceptions use standard behaviors
+    (immutability and concealment) themselves.
+
+``factories.py``
+    Metaclass component factories:
+
+    - ``produce_class_constructor``: Generate customizable ``__new__`` with
+      hooks
+    - ``produce_class_initializer``: Generate customizable ``__init__`` with
+      hooks
+
+``nomina.py``
+    Public naming types, type aliases, and protocols used throughout the
+    package. Defines interfaces for hooks, verifiers, and core functions.
+
+``utilities.py``
+    Class manipulation utilities:
+
+    - ``mangle_name``: Create unique attribute names
+    - ``getattr0/setattr0/delattr0``: Mangled attribute access
+    - ``repair_class_reproduction``: Fix closures after class replacement
+    - ``describe_object``: Generate error message descriptions
+
+Standard Subpackage (``sources/classcore/standard/``)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+``__.py``
+    Inherits all imports from parent ``__`` via ``from ..__ import *``.
+    Demonstrates the cascading import pattern for subpackages.
+
+``__init__.py``
+    Subpackage entry point. Exports all standard classes, decorators, and
+    utilities. Applies standard behaviors to subpackage module.
+
+``behaviors.py``
+    Core implementation of standard behaviors:
+
+    - ``assign_attribute_if_mutable``: Conditional attribute assignment
+    - ``delete_attribute_if_mutable``: Conditional attribute deletion
+    - ``survey_visible_attributes``: Filter attributes for ``dir()``
+    - Verifier processing for names, regexes, and predicates
+
+``classes.py``
+    Standard metaclasses and base classes:
+
+    - ``Class`` / ``Object``: Standard class with full behaviors
+    - ``Dataclass`` / ``DataclassObject``: Auto-dataclass with behaviors
+    - ``Protocol`` / ``ProtocolObject``: Protocol with behaviors
+    - Mutable variants for each
+
+``decorators.py``
+    Standard class decorators:
+
+    - ``class_with_standard_behaviors``: Apply behaviors to existing class
+    - ``dataclass_with_standard_behaviors``: Create dataclass with behaviors
+    - ``protocol_with_standard_behaviors``: Create protocol with behaviors
+    - ``class_factory``: Generic factory for creating custom metaclasses
+
+``dynadoc.py``
+    Dynadoc configuration for standard behaviors. Provides documentation
+    fragments that describe behaviors automatically applied to classes.
+
+``modules.py``
+    Module reclassification utilities:
+
+    - ``reclassify_module``: Apply behaviors to single module
+    - ``finalize_module``: Complete module initialization (used by package)
+
+``nomina.py``
+    Standard-specific naming types and constants. Defines behavior labels
+    and attribute naming functions.
 
 All package modules use the standard ``__`` import pattern as documented
 in the common architecture guide.
 
 Component Integration
 ===============================================================================
 
+Import Hub Usage
+-------------------------------------------------------------------------------
+
+All modules access common dependencies through the ``__`` import hub:
+
+.. code-block:: python
+
+    # In any module at sources/classcore/
+    from . import __
+
+    # Use abbreviated imports
+    def example( items: __.cabc.Sequence[ str ] ) -> __.typx.Any:
+        return __.funct.partial( some_function, items )
+
+This pattern:
+
+- Eliminates redundant import statements
+- Provides consistent naming across modules
+- Centralizes import changes to ``__/imports.py``
+- Reduces module namespace pollution
+
+Subpackage Extension
+-------------------------------------------------------------------------------
+
+The ``standard/`` subpackage demonstrates the cascading import pattern.
+Its ``__.py`` inherits parent imports and can add specialized dependencies:
+
+.. code-block:: python
+
+    # sources/classcore/standard/__.py
+    from ..__ import *              # Inherit all parent imports
+    from ..exceptions import *      # Add package exceptions
+
+Modules in ``standard/`` use the same import pattern but gain access to both
+parent and subpackage-specific imports.
+
 Architecture Evolution
 ===============================================================================