feat(generate): default structure_definition and base_path when omitted (#114)

Summary
This PR improves the UX of the generate command by making both
positional arguments optional with sensible defaults. Users can now run
struct generate with no additional arguments when a .struct.yaml is
present in the current directory.

Motivation
- Streamline the most common workflow: running generation from the
current directory using a local .struct.yaml.
- Reduce friction and boilerplate for quick iterations and demos.

Changes
- CLI: Make positional args optional in GenerateCommand
  - structure_definition defaults to .struct.yaml
  - base_path defaults to .
  - Explicitly provided arguments continue to override these defaults.
- Docs: Updated to reflect new defaults
  - docs/cli-reference.md
  - docs/usage.md
  - docs/quickstart.md

Usage
```sh
# With defaults (if .struct.yaml exists in the current directory)
struct generate

# From a specific YAML file into a target directory (unchanged)
struct generate file://my-config.yaml ./output

# Using a built-in structure definition into a directory (unchanged)
struct generate python-basic ./my-project
```

Backward compatibility
- Existing commands remain valid; this is an additive improvement.
- Explicit arguments still take precedence over defaults.

Testing
- Full test suite executed locally: 112 tests passed.
- No behavior changes to existing flows other than allowing omitted
positional args with sensible defaults.

Docs
- CLI reference updated to show optional positional args and defaults.
- Usage and Quickstart updated with examples using struct generate
without arguments.

Closes #113.

Author: httpdss

docs/cli-reference.md

@@ -59,13 +59,22 @@ Generate the project structure.
 **Usage:**
 
 ```sh
-struct generate [-h] [-l LOG] [-c CONFIG_FILE] [-i LOG_FILE] [-s STRUCTURES_PATH] [-n INPUT_STORE] [-d] [--diff] [-v VARS] [-b BACKUP] [-f {overwrite,skip,append,rename,backup}] [-p GLOBAL_SYSTEM_PROMPT] [--non-interactive] [--mappings-file MAPPINGS_FILE] [-o {console,file}] structure_definition base_path
+struct generate [-h] [-l LOG] [-c CONFIG_FILE] [-i LOG_FILE] [-s STRUCTURES_PATH] [-n INPUT_STORE] [-d] [--diff] [-v VARS] [-b BACKUP] [-f {overwrite,skip,append,rename,backup}] [-p GLOBAL_SYSTEM_PROMPT] [--non-interactive] [--mappings-file MAPPINGS_FILE] [-o {console,file}] [structure_definition] [base_path]
+```
+
+Defaults when omitted:
+- structure_definition -> .struct.yaml
+- base_path -> .
+
+Example:
+```sh
+struct generate
 ```
 
 **Arguments:**
 
-- `structure_definition`: Path to the YAML configuration file.
-- `base_path`: Base path where the structure will be created.
+- `structure_definition` (optional): Path to the YAML configuration file (default: `.struct.yaml`).
+- `base_path` (optional): Base path where the structure will be created (default: `.`).
 - `-s STRUCTURES_PATH, --structures-path STRUCTURES_PATH`: Path to structure definitions.
 - `-n INPUT_STORE, --input-store INPUT_STORE`: Path to the input store.
 - `-d, --dry-run`: Perform a dry run without creating any files or directories.
@@ -139,6 +148,14 @@ struct init [path]
 
 ## Examples
 
+### Using Defaults
+
+Generate with default structure (.struct.yaml) into current directory:
+
+```sh
+struct generate
+```
+
 ### Basic Structure Generation
 
 Generate a structure using a built-in definition:

docs/quickstart.md

@@ -43,7 +43,7 @@ vim structure.yaml # copy the content from the example folder
 struct generate structure.yaml .
 ```
 
-> **Note**: The `file://` protocol is automatically added for `.yaml` files, so `structure.yaml` and `file://structure.yaml` work identically.
+> Note: The `file://` protocol is automatically added for `.yaml` files, so `structure.yaml` and `file://structure.yaml` work identically. Additionally, if your file is named `.struct.yaml` in the current directory and you want to generate into the current directory, you can just run `struct generate`.
 
 ## Discovering Available Structures
 

docs/usage.md

@@ -33,6 +33,14 @@ struct generate <Tab>
 # Shows all available structures
 ```
 
+### Using Defaults
+
+If you have a .struct.yaml in the current directory and want to generate into the current directory, you can simply run:
+
+```sh
+struct generate
+```
+
 ### Simple Example
 
 ```sh
@@ -49,6 +57,12 @@ struct generate my-config.yaml ./output
 struct generate file://my-config.yaml ./output
 ```
 
+Tip: If your config file is named `.struct.yaml` in the current directory and you want to generate into the current directory, you can simply run:
+
+```sh
+struct generate
+```
+
 ### Diff Preview Example
 
 ```sh

struct_module/commands/generate.py

@@ -13,9 +13,9 @@ class GenerateCommand(Command):
   def __init__(self, parser):
     super().__init__(parser)
     parser.description = "Generate the project structure from a YAML configuration file"
-    structure_arg = parser.add_argument('structure_definition', type=str, help='Path to the YAML configuration file')
+    structure_arg = parser.add_argument('structure_definition', nargs='?', default='.struct.yaml', type=str, help='Path to the YAML configuration file (default: .struct.yaml)')
     structure_arg.completer = structures_completer
-    parser.add_argument('base_path', type=str, help='Base path where the structure will be created')
+    parser.add_argument('base_path', nargs='?', default='.', type=str, help='Base path where the structure will be created (default: current directory)')
     parser.add_argument('-s', '--structures-path', type=str, help='Path to structure definitions')
     parser.add_argument('-n', '--input-store', type=str, help='Path to the input store', default='/tmp/struct/input.json')
     parser.add_argument('-d', '--dry-run', action='store_true', help='Perform a dry run without creating any files or directories')