fix: MCP server dispatch — add proper tools/call handler

[alderpath]

Problem

The MCP server advertised 7 tools in tools/list but had no tools/call handler. Every tool invocation via standard MCP protocol returned method not found. The code was checking for non-standard method names like tools/search and tools/compress that no MCP client ever sends.

Fix

• Added tools/call handler that dispatches by params.name (e.g., reliary_search, reliary_compress)
• Results wrapped in MCP-standard content: [{ type: "text", text: ... }] format
• tool_definitions() extracted as shared function used by both tools/list and dispatch logic
• Proper required fields in all tool schemas
• Unknown tool names return standard -32601 error code

Tests

• 5 unit tests (tool definitions validation, response format, compress/unknown/search handlers)
• 3 e2e tests (full tool list + call cycle, error handling, old dispatch rejection)
• All pass in both debug and release