chore: add Zed project config, .editorconfig and shared pyright settings

- .zed/settings.json: ruff + basedpyright for Python (no format on save, the
  tree is not ruff-format clean), ESLint fixes then Prettier for the frontend,
  scan exclusions for caches and build outputs, .jwt_secret_key as private
- .zed/tasks.json: dev services, API, worker, frontend, pytest/vitest for the
  current file or test, linting, uv lock + requirements export
- .zed/debug.json: debugpy targets matching .vscode/launch.json
- .editorconfig: whitespace rules for every editor
- [tool.pyright] in pyproject.toml: venv, import root and excludes shared by
  pyright, basedpyright and Pylance
- .gitignore: track only the shared files under .zed/
- CONTRIBUTING: editor setup section; fix the stale ESLint config path

.zed/debug.json

@@ -0,0 +1,44 @@
+// Debug configurations for the Zed editor (https://zed.dev/docs/debugger),
+// the counterparts of .vscode/launch.json. Start one with `debugger: start`.
+// Zed picks the interpreter from the checkout's `.venv`.
+[
+  {
+    "label": "API (uvicorn)",
+    "adapter": "Debugpy",
+    "request": "launch",
+    "module": "uvicorn",
+    "args": ["docsgpt.asgi:asgi_app", "--host", "127.0.0.1", "--port", "7091"],
+    "cwd": "$ZED_WORKTREE_ROOT",
+    "env": { "PYTHONPATH": "$ZED_WORKTREE_ROOT" },
+    "justMyCode": true
+  },
+  {
+    // The solo pool keeps tasks in the debugged process, so breakpoints hit.
+    "label": "Celery worker (solo pool)",
+    "adapter": "Debugpy",
+    "request": "launch",
+    "module": "celery",
+    "args": ["-A", "docsgpt.app.celery", "worker", "-l", "INFO", "--pool=solo"],
+    "cwd": "$ZED_WORKTREE_ROOT",
+    "env": { "PYTHONPATH": "$ZED_WORKTREE_ROOT" },
+    "justMyCode": true
+  },
+  {
+    "label": "pytest: this file",
+    "adapter": "Debugpy",
+    "request": "launch",
+    "module": "pytest",
+    "args": ["--no-cov", "$ZED_RELATIVE_FILE"],
+    "cwd": "$ZED_WORKTREE_ROOT",
+    "env": { "PYTHONPATH": "$ZED_WORKTREE_ROOT" },
+    "justMyCode": false
+  },
+  {
+    "label": "Python: this file",
+    "adapter": "Debugpy",
+    "request": "launch",
+    "program": "$ZED_FILE",
+    "cwd": "$ZED_WORKTREE_ROOT",
+    "env": { "PYTHONPATH": "$ZED_WORKTREE_ROOT" }
+  }
+]