fix(fit): restore gradio arg alignment + stop masking wiring errors as payload_too_long

- 61aae8d inserted link_lifetime mid-signature; gradio passes UI values
positionally, shifting every arg after use_temporary_short_link by one:
image_size got border (4px), error_correction got module_size int, so the
EC-label dict KeyError'd and _safe_compute masked it as overflow — a 100%
payload_too_long wall on the space UI since 2026-08-04.
- Move link_lifetime to keyword-only in generate_standard_qr and
generate_artistic_qr; gradio's 26/43 positional inputs align again.
Modal/gateway path (build_generation_kwargs, by-name) unaffected.
- qr_fit._safe_compute now converts only true capacity overflows
(DataOverflowError / qrcode 'Invalid version' ValueError) to None; anything
else is logged and re-raised so broken wiring surfaces as the real error
instead of a fake payload_too_long.

app.py

@@ -2993,7 +2993,6 @@ def generate_standard_qr(
     text_input: str = "",
     input_type: str = "URL",
     use_temporary_short_link: bool = False,
-    link_lifetime: str | None = None,
     image_size: int = 512,
     border_size: int = 4,
     error_correction: str = "Medium (15%)",
@@ -3015,6 +3014,8 @@ def generate_standard_qr(
     gradient_strength: float = 0.3,
     variation_steps: int = 5,
     analytics_opt_in: bool = False,
+    *,
+    link_lifetime: str | None = None,
     progress=gr.Progress(),
     request: Union[gr.Request, None] = None,
 ):
@@ -3304,7 +3305,6 @@ def generate_artistic_qr(
     text_input: str = "",
     input_type: str = "URL",
     use_temporary_short_link: bool = False,
-    link_lifetime: str | None = None,
     image_size: int = 512,
     border_size: int = 4,
     error_correction: str = "Medium (15%)",
@@ -3343,6 +3343,8 @@ def generate_artistic_qr(
     gradient_strength: float = 0.3,
     variation_steps: int = 5,
     analytics_opt_in: bool = False,
+    *,
+    link_lifetime: str | None = None,
     progress=gr.Progress(),
     request: Union[gr.Request, None] = None,
 ):

qr_fit.py

@@ -15,6 +15,8 @@ redundancy) → and only then raise a structured payload_too_long error.
 must return the QR pixel size for those settings (matrix modules × module size).
 """
 
+import traceback
+
 PAYLOAD_TOO_LONG_ERROR_CLASS = "payload_too_long"
 
 _EC_NOTCH_DOWN = {
@@ -69,11 +71,27 @@ def auto_fit_qr_dimensions(
 
     def _safe_compute(b: int, e: str, m: int) -> int | None:
         """Pixel size for these settings, or None if the payload exceeds QR
-        capacity at this error-correction level (matrix can't be built)."""
+        capacity at this error-correction level (matrix can't be built).
+
+        Only a true capacity overflow is converted to None: qrcode's
+        DataOverflowError, or the ValueError("Invalid version ...") that
+        qrcode 7.x/8.x raise from make(fit=True) when the payload needs a
+        version beyond 40 (both matched by name/message to keep this module
+        dependency-free). Any other exception means broken caller wiring (bad
+        label, shifted args, type error) — log it loudly and re-raise so it
+        surfaces as the real error instead of a misleading payload_too_long
+        wall."""
         try:
             return compute(border_size=b, error_correction=e, module_size=m)
-        except Exception:
-            return None
+        except Exception as exc:
+            is_capacity = type(exc).__name__ == "DataOverflowError" or (
+                isinstance(exc, ValueError) and "Invalid version" in str(exc)
+            )
+            if is_capacity:
+                return None
+            print("[qr_fit] compute raised a NON-capacity error — re-raising:")
+            traceback.print_exc()
+            raise
 
     # Fast path: fits as requested — byte-identical settings, no adjustment.
     required = _safe_compute(border, ec, mod)