feat(booth): multi-question asks — a questions list renders one form with a radio group per question and lands as one answer sidecar keyed by question

- asks.py: single {prompt, options} and multi {title, questions:[{key, prompt, options, notes?}]} both normalise to questions[]; per-question notes; every question required on submit
- /answer reads choice.<key> / notes.<key> / notes for multi; single shape unchanged
- booth asks prints per-question picks; README + CLI header; install step symlinks the CLI to ~/.local/bin; v0.1.10; 135 tests

booth/app.py

@@ -82,6 +82,7 @@ from booth.asks import (  # noqa: E402
     is_answer_file,
     is_ask_file,
     list_asks,
+    load_ask,
     valid_stem,
     write_answer,
 )
@@ -654,18 +655,30 @@ def create_app(
         )
 
     @app.post("/b/{name}/answer")
-    def booth_answer(request: Request, name: str, ask: str = Form(...), choice: str = Form(...),
-                     notes: str = Form("")):
-        """Record the operator's answer to one ask: validates the choice
-        against the ask's options and writes `<stem>.answer.json` atomically.
-        Re-submitting overwrites — the sidecar is the current answer. 404 for
-        an unknown/invalid stem, 400 for a choice the ask does not offer."""
+    async def booth_answer(request: Request, name: str):
+        """Record the operator's answer to one ask: validates every choice
+        against the ask and writes `<stem>.answer.json` atomically.
+        Re-submitting overwrites — the sidecar is the current answer.
+
+        Form fields: `ask` (stem); single-question → `choice` + `notes`;
+        multi-question → `choice.<key>` per question, optional `notes.<key>`,
+        plus the form-level `notes`. 404 for an unknown/invalid stem, 400 for
+        a missing choice or one the ask does not offer.
+        """
         booth = resolve_booth(name)
-        if not valid_stem(ask) or not (booth / f"{ask}{ASK_SUFFIX}").is_file():
+        form = await request.form()
+        ask = form.get("ask")
+        if not isinstance(ask, str) or not valid_stem(ask) or not (booth / f"{ask}{ASK_SUFFIX}").is_file():
             raise HTTPException(status_code=404, detail="no such ask")
         who = request.client.host if request.client else ""
         try:
-            write_answer(booth, ask, choice, notes, who=who)
+            spec = load_ask(booth, ask)
+            if spec["multi"]:
+                choice = {q["key"]: form.get(f"choice.{q['key']}") for q in spec["questions"]}
+                qnotes = {q["key"]: form.get(f"notes.{q['key']}") for q in spec["questions"]}
+                write_answer(booth, ask, choice, form.get("notes", ""), who=who, qnotes=qnotes)
+            else:
+                write_answer(booth, ask, form.get("choice"), form.get("notes", ""), who=who)
         except AskError as exc:
             raise HTTPException(status_code=400, detail=str(exc))
         return RedirectResponse(url=f"/b/{quote(name, safe='')}/#ask-{quote(ask, safe='')}", status_code=303)