Standalone Shonar Desktop: vendor portable sources + local engine; decouple from ~/Projects/Shonar

- shared/ = portable Android-origin sources vendored from deferred/desktop-server
  (app/build.gradle.kts srcDir repointed; PlaybackController.kt excluded as Android-only)
- backend/ = bundled-lite engine (SQLite + inline queue); .venv symlinked from the
  old checkout, PYTHONPATH pins THIS backend's code over any editable install
- repoRoot() resolves this project dir (env SHONAR_REPO still wins); desktop-dev.sh
  watches shared/ + backend/
- Verified: :app:compileKotlin + :app:test green (23 tests); engine boots on :8010,
  self-migrates, /healthz ok

backend/pyproject.toml

@@ -0,0 +1,64 @@
+[project]
+name = "shonar-backend"
+version = "0.1.0"
+description = "S.H.O.N.A.R. — Self-hosted Oral Notes and Audio Recorder backend"
+readme = "README.md"
+requires-python = ">=3.11"
+license = { text = "Apache-2.0" }
+dependencies = [
+    "fastapi>=0.115",
+    "uvicorn[standard]>=0.30",
+    "sqlalchemy[asyncio]>=2.0",
+    "asyncpg>=0.29",
+    "aiosqlite>=0.20",          # tests only in practice; harmless dep
+    "alembic>=1.13",
+    "pydantic>=2.8",
+    "pydantic-settings>=2.4",
+    "email-validator>=2.0",
+    "argon2-cffi>=23.1",
+    "pyjwt>=2.9",
+    "python-multipart>=0.0.9",
+    "slowapi>=0.1.9",
+    "redis>=5.0",
+    "arq>=0.26",
+]
+
+[project.optional-dependencies]
+s3 = ["boto3>=1.34"]
+faster-whisper = ["faster-whisper>=1.0"]
+dev = [
+    "pytest>=8.0",
+    "pytest-asyncio>=0.23",
+    "httpx>=0.27",
+    "ruff>=0.5",
+    "mypy>=1.10",
+]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["shonar"]
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"
+asyncio_default_fixture_loop_scope = "session"
+asyncio_default_test_loop_scope = "session"
+testpaths = ["tests"]
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+exclude = ["migrations"]
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "UP", "B", "SIM"]
+
+[tool.ruff.lint.per-file-ignores]
+# FastAPI idiom: Query(...)/Depends() as parameter defaults.
+"shonar/api/**" = ["B008"]
+
+[tool.mypy]
+python_version = "3.11"
+ignore_missing_imports = true