fix: stabilize runtime follow-up regressions

site/doc/pages/to_bool.txt

@@ -1,5 +1,9 @@
 :sig
-bool DTree::to_bool()
+bool DTree::to_bool(bool default_value = false) const
+
+:params
+default_value : returned when the value is missing or empty
+return value : the value as a boolean, or `default_value`
 
 :see
 >types
@@ -7,12 +11,27 @@ bool DTree::to_bool()
 json_decode
 to_f64
 to_u64
+to_string
 
 :content
-Reads a `DTree` value as a boolean.
+Reads a `DTree` value as a boolean. This is a read accessor: it is `const`, never creates or modifies nodes, and dereferences internal references automatically.
 
-String values such as `true`, `yes`, `on`, and `1` read as true. Values such as `false`, `no`, `off`, `0`, and `null` read as false.
+String values such as `true`, `yes`, `on`, and `1` read as true. Values such as `false`, `no`, `off`, `0`, and `null` read as false. Numeric values read as true when non-zero.
 
-Numeric values read as true when non-zero. Empty strings read as false.
+`default_value` is returned when the node is unset, holds an empty string, or is an unresolvable reference. Note the truthiness rule: a non-empty string that parses as neither a boolean word nor a number still reads as `true` — only missing/empty values fall back to the default.
+
+A map-shaped node with exactly one entry unwraps to that entry's value; other maps read as true when non-empty.
+
+## Example
+
+```cpp
+bool log_requests = context.cfg.get_by_path("app/log_requests").to_bool(true);
+bool wants_compact = context.props["compact"].to_bool();
+```
 
 Use this when consuming request data, JSON-decoded values, config trees, or component props where the original input may be string-shaped.
+
+## Related Concepts
+
+- PHP: `filter_var($v, FILTER_VALIDATE_BOOLEAN)`
+- JavaScript: `Boolean(value)` plus string handling