feat: versioning SemVer MAJOR.MINOR.PATCH basé sur git describe

- backend/version.py: get_version() lit git describe --tags (ex: 1.8.0-301-gabc1234)
- main.py: FastAPI version = get_version() dynamique
- build.rs: injecte GIT_VERSION, GIT_HASH, SEMVER depuis git describe
- main.rs: ABOUT_MSG, get_version(), log utilisent GIT_VERSION
- Format: MAJOR.MINOR.PATCH[-commits-gHASH] (ex: 1.8.0, 1.8.0-3-gabc1234)
- Fallback: VERSION file ou 0.0.0-dev si Git indisponible

backend/main.py

@@ -633,7 +633,9 @@ async def lifespan(app: FastAPI):
     _search_executor = None
 
 
-app = FastAPI(title="ObsiGate", version="1.4.0", lifespan=lifespan)
+from backend.version import get_version
+
+app = FastAPI(title="ObsiGate", version=get_version(), lifespan=lifespan)
 
 # GZip compression — reduces bandwidth by ~70% for text responses
 # Custom wrapper: skip compression for SSE streams (/api/events)

backend/version.py

@@ -0,0 +1,64 @@
+"""
+Version management for ObsiGate.
+
+Uses git describe to generate a SemVer-compatible version string.
+Format: MAJOR.MINOR.PATCH[-commits-since-tag-gHASH]
+
+Examples:
+  v1.7.0                    (exact tag)
+  v1.7.0-3-gabc1234         (3 commits after v1.7.0)
+  v1.7.0-dev                (fallback when Git unavailable)
+"""
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+
+_ROOT = Path(__file__).resolve().parent.parent  # ObsiGate repo root
+
+
+def get_version() -> str:
+    """Get the current version from Git tags."""
+    try:
+        result = subprocess.run(
+            ["git", "describe", "--tags", "--dirty=-dirty"],
+            cwd=str(_ROOT),
+            capture_output=True,
+            text=True,
+            timeout=5,
+        )
+        if result.returncode == 0:
+            tag = result.stdout.strip()
+            # git describe returns v1.7.0 or v1.7.0-3-gabc1234
+            # Remove leading 'v' if present
+            if tag.startswith("v"):
+                tag = tag[1:]
+            return tag
+    except (FileNotFoundError, subprocess.TimeoutExpired, OSError):
+        pass
+
+    # Fallback: try reading from a VERSION file
+    version_file = _ROOT / "VERSION"
+    if version_file.exists():
+        return version_file.read_text().strip()
+
+    return "0.0.0-dev"
+
+
+def get_version_tuple() -> tuple[int, int, int]:
+    """Return (major, minor, patch) tuple for programmatic use."""
+    raw = get_version()
+    # Strip -suffix for parsing
+    base = raw.split("-")[0]
+    try:
+        parts = base.split(".")
+        major = int(parts[0]) if len(parts) > 0 else 0
+        minor = int(parts[1]) if len(parts) > 1 else 0
+        patch = int(parts[2]) if len(parts) > 2 else 0
+        return (major, minor, patch)
+    except (ValueError, IndexError):
+        return (0, 0, 0)
+
+
+if __name__ == "__main__":
+    print(get_version())