Convert to setuptools-scm for automatic version management

- Remove manual version management in favor of git tag-based versioning
- Simplify __version__.py to import from generated _version.py
- Add simplified release_simplified.py script
- Add _version.py to .gitignore (auto-generated)

🚀 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

markitect/__version__.py

@@ -1,123 +1,16 @@
 """
 Version information for MarkiTect.
 
-This module provides version and release information for the MarkiTect package.
-Version information is sourced from pyproject.toml and git metadata when available.
+This module provides version information using setuptools-scm.
+Version is automatically derived from git tags.
 """
 
-import os
-import subprocess
-from pathlib import Path
-from typing import Optional
+try:
+    from ._version import version as __version__
+except ImportError:
+    # Fallback when _version.py is not available (e.g., during development without setuptools-scm)
+    __version__ = "unknown"
 
-# Base version from pyproject.toml
-__version__ = "0.5.0"
-
-def get_git_commit_hash() -> Optional[str]:
-    """Get the current git commit hash if available."""
-    try:
-        result = subprocess.run(
-            ['git', 'rev-parse', '--short', 'HEAD'],
-            capture_output=True,
-            text=True,
-            check=True,
-            cwd=Path(__file__).parent.parent
-        )
-        return result.stdout.strip()
-    except (subprocess.CalledProcessError, FileNotFoundError):
-        return None
-
-def get_git_branch() -> Optional[str]:
-    """Get the current git branch if available."""
-    try:
-        result = subprocess.run(
-            ['git', 'branch', '--show-current'],
-            capture_output=True,
-            text=True,
-            check=True,
-            cwd=Path(__file__).parent.parent
-        )
-        return result.stdout.strip()
-    except (subprocess.CalledProcessError, FileNotFoundError):
-        return None
-
-def get_git_tag() -> Optional[str]:
-    """Get the current git tag if available."""
-    try:
-        result = subprocess.run(
-            ['git', 'describe', '--tags', '--exact-match'],
-            capture_output=True,
-            text=True,
-            check=True,
-            cwd=Path(__file__).parent.parent
-        )
-        return result.stdout.strip()
-    except (subprocess.CalledProcessError, FileNotFoundError):
-        return None
-
-def is_development_version() -> bool:
-    """Check if this is a development version (has uncommitted changes)."""
-    try:
-        result = subprocess.run(
-            ['git', 'status', '--porcelain'],
-            capture_output=True,
-            text=True,
-            check=True,
-            cwd=Path(__file__).parent.parent
-        )
-        return bool(result.stdout.strip())
-    except (subprocess.CalledProcessError, FileNotFoundError):
-        return False
-
-def get_version_info() -> dict:
-    """Get comprehensive version information."""
-    git_commit = get_git_commit_hash()
-    git_branch = get_git_branch()
-    git_tag = get_git_tag()
-    is_dev = is_development_version()
-
-    # Build version string
-    version_parts = [__version__]
-
-    if git_tag and git_tag != f"v{__version__}":
-        # If we have a different tag, use it
-        version_parts = [git_tag.lstrip('v')]
-
-    if git_commit:
-        if is_dev:
-            version_parts.append(f"dev+{git_commit}")
-        elif not git_tag:
-            version_parts.append(f"+{git_commit}")
-
-    if is_dev and not git_commit:
-        version_parts.append("dev")
-
-    full_version = ".".join(version_parts)
-
-    return {
-        "version": __version__,
-        "full_version": full_version,
-        "git_commit": git_commit,
-        "git_branch": git_branch,
-        "git_tag": git_tag,
-        "is_development": is_dev,
-        "is_git_repo": git_commit is not None
-    }
-
-def get_release_info() -> dict:
-    """Get release information."""
-    version_info = get_version_info()
-
-    release_type = "development" if version_info["is_development"] else "release"
-    if version_info["git_tag"]:
-        release_type = "tagged-release"
-    elif version_info["git_commit"] and not version_info["is_development"]:
-        release_type = "commit-build"
-
-    return {
-        "release_type": release_type,
-        "build_from": version_info["git_branch"] or "unknown",
-        "commit": version_info["git_commit"] or "unknown",
-        "clean_build": not version_info["is_development"],
-        **version_info
-    }
+def get_version():
+    """Get the current version string."""
+    return __version__