Epic 2: Typed Tool Definitions (M27)

[bug-ops]

Problem

execute_tool_call() manually extracts params from HashMap<String, Value> with no type safety. Param structs derive JsonSchema but not Deserialize — they are dead-code schema-only markers.

Solution

Make param structs derive Deserialize, deserialize ToolCall.params into typed structs via serde_json::from_value.

Issues

• refactor(tools): typed deserialization for tool call params #460 refactor(tools): typed deserialization for tool call params size/S
• refactor(tools): extract deserialize_params<T> helper #461 refactor(tools): extract deserialize_params<T> helper size/XS

Verification

Verify tool params deserialize without manual extraction.