Scaffold project, data model and artwork

Establish the LLeMbas foundation: FastAPI/Jinja/SQLite layout, the ORM
schema, and the original SVG identity.

Notable decisions, all recorded in comments at the point they matter:

- No Alembic. SQLite only, schema created at startup, so models carry a
  few columns nothing reads yet (Message.parent_id for branching,
  content_parts_json for multimodal turns). Adding them later to a live
  database without migrations is the painful path.
- Sessions are server-side rows keyed by a SHA-256 of the cookie value,
  not JWTs, so logout and bans revoke access immediately.
- Upstream API keys are Fernet-encrypted with a key derived from
  LEMBAS_SECRET_KEY. decrypt() fails soft to "" so rotating the secret
  degrades to re-entering keys rather than crashing the admin UI.
- Artwork is generated by scripts/build_artwork.py rather than hand-drawn
  per file: the mallorn leaf appears in the icon, favicon, lockup and
  banner, and one source is the only way those stay in sync. The wordmark
  is Source Serif 4 (OFL) converted to outlines, because a README banner
  cannot load a webfont and <text> would render in whatever serif the
  viewer happens to have.
- Icons live in a template partial, not assets/, because same-document
  <use href="#id"> is universally supported and the cross-document form
  is not.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,66 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "lembas"
+version = "0.1.0"
+description = "LLeMbas - a Middle-earth themed web UI for OpenAI-compatible LLM endpoints"
+readme = "README.md"
+requires-python = ">=3.11"
+license = { file = "LICENSE" }
+authors = [{ name = "Jaroslav Benes", email = "admin@ecoposta.sk" }]
+keywords = ["llm", "webui", "openai", "chat", "self-hosted"]
+classifiers = [
+    "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
+    "Programming Language :: Python :: 3",
+    "Topic :: Communications :: Chat",
+]
+
+dependencies = [
+    "fastapi>=0.115",
+    "uvicorn[standard]>=0.32",
+    "jinja2>=3.1",
+    "sqlalchemy>=2.0",
+    "pydantic>=2.9",
+    "pydantic-settings>=2.6",
+    "httpx>=0.27",
+    "python-multipart>=0.0.12",
+    "argon2-cffi>=23.1",
+    "cryptography>=43.0",
+    "markdown-it-py>=3.0",
+    "mdit-py-plugins>=0.4",
+    "pygments>=2.18",
+    "nh3>=0.2.18",
+    "typer>=0.12",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.3",
+    "pytest-asyncio>=0.24",
+    "ruff>=0.7",
+]
+
+[project.scripts]
+lembas = "lembas.cli:app"
+
+[project.urls]
+Homepage = "https://github.com/homer/LLeMbas"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/lembas"]
+
+[tool.ruff]
+line-length = 100
+target-version = "py311"
+src = ["src", "tests"]
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "UP", "B", "SIM", "C4"]
+ignore = ["B008"]  # FastAPI Depends() in defaults is idiomatic
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+asyncio_mode = "auto"
+filterwarnings = ["ignore::DeprecationWarning"]