fix: strip schema titles via schemars SchemaSettings transform

[amitksingh1490]

Summary

Strip Rust-generated title fields from tool schemas at generation time using schemars SchemaSettings transforms, rather than post-hoc in every provider or serializer.

Context

Fixes #3335. The #[derive(JsonSchema)] macro emits a title field containing the Rust struct name (e.g. "title": "FSPatch") for every schema node. These internal type names were being forwarded to LLM provider APIs (Anthropic, OpenAI, Google, Bedrock, Codex), which is confusing and leaks implementation details.

The previous approach patched around the problem by stripping titles in individual places: custom serialize_with/deserialize_with on ToolDefinition.input_schema, a without_schema_titles() call in Context::add_tool, and various provider-specific helpers. This spread the responsibility across many callsites and was fragile.

Changes

• tool_definition.rs: Add RemoveSchemaTitles schemars Transform and tool_schema_generator() — a SchemaGenerator built from SchemaSettings with that transform registered. Schemas generated through this generator never contain title fields.
• tool_definition.rs: Remove strip_schema_titles(), serialize_schema_without_titles, deserialize_schema_without_titles, and without_schema_titles() — all post-hoc stripping helpers are gone.
• tool_definition.rs: ToolDefinition::new() and ToolDefinition::input_schema() now use tool_schema_generator() / plain assignment.
• catalog.rs: ToolCatalog::schema() adds RemoveSchemaTitles to its existing custom SchemaSettings, so all catalog tool schemas are generated title-free.
• agent.rs: Agent tool schema uses tool_schema_generator() instead of schema_for!.
• context.rs: Context::add_tool reverted to a plain push — no more without_schema_titles() call needed.
• Snapshots: Updated to reflect that tool catalog schemas no longer contain title fields.
• Tests: New tests verify that tool_schema_generator() strips titles at the root and recursively in nested schemas, and that round-trip serialization preserves the absence of titles.

Key Implementation Details

schemars SchemaSettings has a transforms: Vec<Box<dyn GenTransform>> field. Any Transform pushed there is applied to every schema produced by the resulting SchemaGenerator (via into_root_schema_for::<T>()). RemoveSchemaTitles implements Transform by removing the "title" key and then calling transform_subschemas to recurse. This is the idiomatic schemars way to post-process generated schemas globally.

Testing

# Run targeted domain tests
cargo test -p forge_domain schema_titles

# Run full domain test suite
cargo insta test -p forge_domain --accept

# Run full workspace
cargo nextest run --all-features --workspace

Links

• Fixes: [Bug]: Minimax 2.7 often times use FSPatch instead of the correct tools which is patch #3335