feat(core): tool-level secure parameter binding, fast-fail and validation

[anubhav756]

Description

Implements immutable secure parameter binding, prompt injection defense, local fast-fail validation, and dynamic callable resolution on ToolboxTool and ToolboxSyncTool.

Changes

• Ensures __signature__, __doc__, __annotations__, and Pydantic validation models are constructed strictly using regular __params. __secure_params is completely isolated.
• Model/caller attempts to supply secure parameter keys in call arguments are blocked by inspect.Signature.bind() raising TypeError: unexpected keyword argument.
• Missing required secure parameters fail locally in __call__ with ValueError before dispatching any network RPCs.
• Supports static values, synchronous callables (lambda: ...), and async coroutines (async def ...) resolved per-invocation via resolve_value().
• Added bind_secure_param(name, value) and bind_secure_params({name: value}) returning new immutable copies via __copy().
• Throws helpful ValueError when attempting to bind secure parameters via bind_param or regular parameters via bind_secure_param.
• Added bind_secure_param / bind_secure_params to ToolboxSyncTool.
• Added test coverage verifying schema isolation, immutable copy semantics, callable resolution, and two-way collision errors.