fix: dereference MCP tool schema $ref/$defs and suppress Ajv format warnings (#276)

- Add dereferenceJsonSchema() that inlines local $ref pointers and strips
  $defs/definitions from MCP tool schemas before they reach LLM providers.
  Previously, Anthropic's convertTools() extracted only properties/required,
  dropping $defs and leaving dangling $ref — the LLM never saw the actual
  type definitions (e.g. SourceAnchorInput enum values from nucleus).

- Silence Ajv logger (logger: false) on all three instances that use
  strict: false. MCP servers may declare non-standard format keywords
  (e.g. "uint") that caused console.warn() to corrupt TUI output.

- Cache compiled Ajv validators per schema object identity in validation.ts,
  eliminating redundant recompilation on every tool call.

Co-authored-by: Miroslav Drbal <miroslav.drbal@gendigital.com>

packages/coding-agent/src/task/executor.ts

@@ -41,7 +41,7 @@ import {
 } from "./types";
 
 const MCP_CALL_TIMEOUT_MS = 60_000;
-const ajv = new Ajv({ allErrors: true, strict: false });
+const ajv = new Ajv({ allErrors: true, strict: false, logger: false });
 
 /** Agent event types to forward for progress tracking. */
 const agentEventTypes = new Set<AgentEvent["type"]>([