fix: stabilize runtime follow-up regressions

site/doc/pages/to_s64.txt

@@ -0,0 +1,41 @@
+:sig
+s64 DTree::to_s64(s64 default_value = 0) const
+
+:params
+default_value : returned when the value is missing or cannot be parsed as a number
+return value : the value as a signed 64-bit integer, or `default_value`
+
+:see
+>types
+0_DTree
+to_u64
+to_f64
+to_bool
+to_string
+
+:content
+Reads a `DTree` value as a signed integer. This is a read accessor: it is `const`, never creates or modifies nodes, and dereferences internal references automatically.
+
+String values are trimmed and parsed permissively: plain integers, floating-point forms (truncated toward zero), and the boolean words understood by `to_bool()` (`yes` reads as `1`) all convert. Results outside the `s64` range clamp to the range boundaries. Boolean values become `1` or `0`.
+
+`default_value` is returned when:
+
+- the node is unset or holds an empty string
+- the string does not parse as a number (`"not-a-number"`)
+- the node is map-shaped with more than one entry, or an unresolvable reference
+
+A map-shaped node with exactly one entry unwraps to that entry's value before converting — this matches how single-value rows from query results read.
+
+## Example
+
+```cpp
+s64 page = context.get["page"].to_s64(1);
+s64 limit = context.cfg.get_by_path("app/page_size").to_s64(25);
+```
+
+`json_decode()` stores JSON numbers as string-valued nodes, so this is the normal way to consume decoded numeric fields.
+
+## Related Concepts
+
+- PHP: `intval()` with a fallback
+- JavaScript: `parseInt(x) || fallback`