Add browser Python editor with Pyodide, user auth, and workspace API

- FastAPI serves static UI, file CRUD under code/ and read-only lib/
- Pyodide worker runs Python and Jedi completions in the browser
- SQLite accounts: login/register, session cookies, superuser user management
- Optional EDITOR_API_KEY, AUTH_* env vars, .env.example
- Pipenv, pytest, Selenium smoke test, README

Made-with: Cursor

src/static/pyodide-worker.js

@@ -0,0 +1,122 @@
+/* global importScripts, loadPyodide, self */
+importScripts('https://cdn.jsdelivr.net/pyodide/v0.26.4/full/pyodide.js');
+
+const PYODIDE_INDEX_URL = 'https://cdn.jsdelivr.net/pyodide/v0.26.4/full/';
+
+let pyodide = null;
+let loadingPromise = null;
+
+async function ensurePyodide() {
+  if (pyodide) {
+    return pyodide;
+  }
+  if (!loadingPromise) {
+    loadingPromise = (async () => {
+      const p = await loadPyodide({ indexURL: PYODIDE_INDEX_URL });
+      p.setStdout({
+        batched: (txt) => self.postMessage({ type: 'io', stream: 'stdout', text: txt }),
+      });
+      p.setStderr({
+        batched: (txt) => self.postMessage({ type: 'io', stream: 'stderr', text: txt }),
+      });
+      await p.loadPackage('micropip');
+      await p.runPythonAsync(`
+import micropip
+await micropip.install("jedi")
+`);
+      return p;
+    })();
+  }
+  pyodide = await loadingPromise;
+  return pyodide;
+}
+
+self.onmessage = async (event) => {
+  const { id, type, payload } = event.data || {};
+  try {
+    if (type === 'init') {
+      await ensurePyodide();
+      self.postMessage({ id, type: 'init', ok: true });
+      return;
+    }
+
+    const p = await ensurePyodide();
+
+    if (type === 'complete') {
+      const rel = String(payload.path || 'scratch.py').replace(/^\/+/, '');
+      const vpath = `/workspace/${rel}`;
+      p.globals.set('__cm_code', String(payload.content ?? ''));
+      p.globals.set('__cm_path', vpath);
+      p.globals.set('__cm_line', Number(payload.line) || 1);
+      p.globals.set('__cm_col', Number(payload.column) || 0);
+      p.globals.set('__cm_max', Math.min(100, Math.max(1, Number(payload.max_results) || 20)));
+      p.globals.set('__cm_extra_json', JSON.stringify(payload.extra_files || {}));
+      const raw = p.runPython(`
+import json, os
+import jedi
+
+extra = json.loads(__cm_extra_json)
+os.makedirs("/workspace", exist_ok=True)
+for rel_path, body in extra.items():
+    rel_path = str(rel_path).lstrip("/")
+    full = os.path.join("/workspace", rel_path)
+    os.makedirs(os.path.dirname(full), exist_ok=True)
+    with open(full, "w", encoding="utf-8") as fh:
+        fh.write(str(body))
+os.makedirs(os.path.dirname(__cm_path), exist_ok=True)
+with open(__cm_path, "w", encoding="utf-8") as fh:
+    fh.write(__cm_code)
+proj = jedi.Project("/workspace")
+s = jedi.Script(code=__cm_code, path=__cm_path, project=proj)
+items = s.complete(line=__cm_line, column=__cm_col)
+out = [{"name": i.name, "type": i.type, "complete": i.complete} for i in items[:__cm_max]]
+json.dumps(out)
+`);
+      const completions = JSON.parse(String(raw));
+      self.postMessage({ id, type: 'complete', ok: true, completions });
+      return;
+    }
+
+    if (type === 'run') {
+      const files = payload.files && typeof payload.files === 'object' ? payload.files : {};
+      const mainRel = String(payload.mainPath || '').replace(/^\/+/, '');
+      const argsList = Array.isArray(payload.args) ? payload.args.map(String) : [];
+      p.globals.set('__run_files_json', JSON.stringify(files));
+      p.globals.set('__run_main', `/workspace/${mainRel}`);
+      p.globals.set('__run_args', p.toPy(argsList));
+      await p.runPythonAsync(`
+import json, os, shutil, sys, runpy
+
+files = json.loads(__run_files_json)
+shutil.rmtree('/workspace', ignore_errors=True)
+os.makedirs('/workspace', exist_ok=True)
+for rel, body in files.items():
+    rel = str(rel).lstrip("/")
+    full = os.path.join("/workspace", rel)
+    os.makedirs(os.path.dirname(full), exist_ok=True)
+    with open(full, "w", encoding="utf-8") as fh:
+        fh.write(str(body))
+
+for entry in ("/workspace/lib", "/workspace"):
+    if entry not in sys.path:
+        sys.path.insert(0, entry)
+
+os.chdir("/workspace")
+main = __run_main
+sys.argv = [main] + list(__run_args)
+runpy.run_path(main, run_name="__main__")
+`);
+      self.postMessage({ id, type: 'run', ok: true });
+      return;
+    }
+
+    self.postMessage({ id, type, ok: false, error: `Unknown message type: ${type}` });
+  } catch (err) {
+    self.postMessage({
+      id,
+      type,
+      ok: false,
+      error: err && err.message ? String(err.message) : String(err),
+    });
+  }
+};