📝 docs: move spec parsing to tutorial, enlarge logo

Move the PythonSpec parsing section from how-to to the tutorial
where it fits the learning flow better. Scale the SVG logo from
24x24 to 128x128 pixels.

Author: gaborbernat

docs/_static/logo.svg

@@ -151,34 +151,3 @@ A :class:`~py_discovery.PythonInfo` object exposes detailed interpreter metadata
    info.platform             # sys.platform value ("linux", "darwin", "win32").
    info.sysconfig_vars       # Dict of sysconfig variables.
    info.sysconfig_paths      # Dict of sysconfig paths.
-
-Parsing specs without discovery
--------------------------------
-
-Use :class:`~py_discovery.PythonSpec` to parse a spec string without running discovery.
-
-.. mermaid::
-
-    flowchart TD
-        Input["cpython3.12t-64-arm64"] --> Parse["PythonSpec.from_string_spec()"]
-        Parse --> Spec["PythonSpec"]
-        Spec --> impl["implementation: cpython"]
-        Spec --> ver["major: 3, minor: 12"]
-        Spec --> ft["free_threaded: True"]
-        Spec --> arch["architecture: 64"]
-        Spec --> mach["machine: arm64"]
-
-        style Input fill:#4a90d9,stroke:#2a5f8f,color:#fff
-        style Spec fill:#4a9f4a,stroke:#2a6f2a,color:#fff
-
-.. code-block:: python
-
-   from py_discovery import PythonSpec
-
-   spec = PythonSpec.from_string_spec("cpython3.12t-64-arm64")
-   print(spec.implementation)   # cpython
-   print(spec.major)            # 3
-   print(spec.minor)            # 12
-   print(spec.free_threaded)    # True
-   print(spec.architecture)     # 64
-   print(spec.machine)          # arm64

docs/how-to/standalone-usage.rst

@@ -99,6 +99,37 @@ Specs follow the pattern ``[impl][version][t][-arch][-machine]``.
 - ``>=3.11,<3.13`` -- :pep:`440` version specifier.
 - ``cpython>=3.11`` -- :pep:`440` specifier with implementation filter.
 
+Parsing a spec
+--------------
+
+Use :class:`~py_discovery.PythonSpec` to parse a spec string into its components without running discovery.
+
+.. mermaid::
+
+    flowchart TD
+        Input["cpython3.12t-64-arm64"] --> Parse["PythonSpec.from_string_spec()"]
+        Parse --> Spec["PythonSpec"]
+        Spec --> impl["implementation: cpython"]
+        Spec --> ver["major: 3, minor: 12"]
+        Spec --> ft["free_threaded: True"]
+        Spec --> arch["architecture: 64"]
+        Spec --> mach["machine: arm64"]
+
+        style Input fill:#4a90d9,stroke:#2a5f8f,color:#fff
+        style Spec fill:#4a9f4a,stroke:#2a6f2a,color:#fff
+
+.. code-block:: python
+
+   from py_discovery import PythonSpec
+
+   spec = PythonSpec.from_string_spec("cpython3.12t-64-arm64")
+   print(spec.implementation)   # cpython
+   print(spec.major)            # 3
+   print(spec.minor)            # 12
+   print(spec.free_threaded)    # True
+   print(spec.architecture)     # 64
+   print(spec.machine)          # arm64
+
 Without caching
 ---------------