Add release script and bump version to 0.4.3

Belated commit: 0.4.3 was published to PyPI on 2026-08-04 with this
state (scripts/release.py automates the version bump and build).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/release.py

@@ -0,0 +1,67 @@
+"""Bump version, clean old artifacts, build web + package.
+
+Run from the gcontext/ directory:
+    uv run python scripts/release.py <new-version>
+
+Produces wheel + sdist in dist/. Does NOT publish; the agent handles
+that through the pypi connection.
+"""
+
+import re
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parent.parent  # gcontext/
+PYPROJECT = REPO / "pyproject.toml"
+DIST = REPO / "dist"
+
+
+def bump_version(new: str) -> str:
+    text = PYPROJECT.read_text()
+    match = re.search(r'^version\s*=\s*"([^"]+)"', text, re.MULTILINE)
+    if not match:
+        sys.exit("could not find version in pyproject.toml")
+    old = match.group(1)
+    if old == new:
+        sys.exit(f"version is already {new}")
+    updated = text.replace(f'version = "{old}"', f'version = "{new}"')
+    PYPROJECT.write_text(updated)
+    print(f"version: {old} -> {new}")
+    return old
+
+
+def clean_dist():
+    if DIST.exists():
+        shutil.rmtree(DIST)
+        print("cleaned dist/")
+
+
+def build():
+    print("building web + package...")
+    result = subprocess.run(["make", "build"], cwd=REPO, capture_output=True, text=True)
+    if result.returncode != 0:
+        print(result.stdout)
+        print(result.stderr, file=sys.stderr)
+        sys.exit(f"build failed (exit {result.returncode})")
+    artifacts = sorted(DIST.glob("gcontext_ai-*"))
+    for a in artifacts:
+        print(f"  {a.name}")
+    if len(artifacts) != 2:
+        sys.exit(f"expected 2 artifacts, got {len(artifacts)}")
+    print("build ok")
+
+
+def main():
+    if len(sys.argv) != 2:
+        sys.exit("usage: uv run python scripts/release.py <new-version>")
+    new_version = sys.argv[1]
+    bump_version(new_version)
+    clean_dist()
+    build()
+    print(f"\nready to publish {new_version}")
+
+
+if __name__ == "__main__":
+    main()