* fix(elicitation): preserve enumNames through ElicitationSchema serde round-trip
UntitledSingleSelectEnumSchema lacked deny_unknown_fields, so a legacy
enum payload containing enumNames was silently matched by that variant
(ignoring the field) rather than falling through to LegacyEnumSchema.
The enumNames array was lost on re-serialization.
Add deny_unknown_fields to UntitledSingleSelectEnumSchema so that any
unknown field (including enumNames) causes serde to try the next
untagged variant, reaching LegacyEnumSchema correctly.
Also add skip_serializing_if = "Option::is_none" to
LegacyEnumSchema::enum_names so that an untitled legacy enum without
enumNames does not serialize "enumNames": null.
Fixes#903
* test(elicitation): regenerate server schema snapshot for deny_unknown_fields
deny_unknown_fields on UntitledSingleSelectEnumSchema makes schemars
emit additionalProperties: false for that definition. Regenerate the
golden schema fixtures to match (UPDATE_SCHEMA=1 cargo test -p rmcp
--test test_message_schema --all-features).
* feat: add type-safe elicitation schema support (#465)
Implement type-safe schema definitions for MCP elicitation requests,
replacing generic `JsonObject` with strongly-typed primitive schemas
per the [MCP 2025-06-18 specification](https://spec.modelcontextprotocol.io/specification/2025-06-18/server/elicitation/).
Features:
- Type-safe schema hierarchy (`StringSchema`, `NumberSchema`, `IntegerSchema`, `BooleanSchema`)
- Builder pattern with fluent API and 20+ convenience methods
- Build-time validation ensuring required fields exist in properties
- Private fields enforcing invariants through validated constructors
- Comprehensive validation support (range, length, format, enums)
- Typed property methods for cleaner schema construction
Benefits:
- Compile-time type safety prevents invalid schema construction
- 60-70% reduction in boilerplate through convenience methods
- Enforces MCP specification requirement for primitive-only properties
- Better IDE autocomplete and type inference
- Runtime validation catches schema errors early
Breaking changes:
- `CreateElicitationRequestParam.requested_schema` changed from `JsonObject` to `ElicitationSchema`
- `ElicitationSchemaBuilder::build()` now returns `Result` instead of direct value
Fixes#465
* fix: fix RMCP compliance
* feat: add conversion methods to ElicitationSchema
Add from_json_schema() and from_type() methods to ElicitationSchema
for easier type-to-schema conversion. This addresses feedback about
improving ergonomics when working with generated schemas.
Also make all struct fields public for better flexibility.
* chore: change `StringFormat` to enum
