feat(core): dynamic tool annotations for multi-mode tools on read-only sources

[anubhav756]

Summary

Enables multi-mode tools (e.g., SQL execution tools) to dynamically advertise readOnlyHint: true and destructiveHint: false in MCP tool manifests when bound to a read-only data source, and centralizes tool suppression logic across the server.

Context & Motivation

• Tools like postgres-execute-sql and mysql-execute-sql are multi-mode (capable of both reads and writes) and default to readOnlyHint: false / destructiveHint: true. When connected to a readOnly: true database source (where session-level locks prevent modifications), these tools should dynamically report readOnlyHint: true and destructiveHint: false to MCP clients without requiring separate read-only tool implementations.
• Refactored ShouldSuppress from a BaseTool method into a package-level function tools.ShouldSuppress(ctx, t, src) that operates on the Tool interface, allowing suppression to dynamically evaluate t.GetAnnotations(src) without requiring concrete tool method overrides.

Changes

• Updated Tool.GetAnnotations(sources.Source) *ToolAnnotations to make annotations source-aware (matching the design pattern of GetParameters(sources.Source) and Manifest(sources.Source)).
• Updated BaseTool.GetAnnotations(_ sources.Source) to return static annotations by default.
• Added DynamicReadOnlyAnnotations(base *ToolAnnotations) *ToolAnnotations in internal/tools/tools.go to safely copy base annotations and set ReadOnlyHint: true / DestructiveHint: false while preserving other custom hints (e.g. idempotentHint, openWorldHint).
• Updated postgres-execute-sql and mysql-execute-sql to implement GetAnnotations(src) using tools.DynamicReadOnlyAnnotations(t.BaseTool.GetAnnotations(src)) when src.IsReadOnly().
• Removed redundant ShouldSuppress method overrides from concrete SQL tool structs.
• Updated all 5 MCP schema version generators (v20241105, v20250326, v20250618, v20251125, v20260728) in internal/server/mcp/ to pass src into tool.GetAnnotations(src).
• Added table-driven tests for tools.DynamicReadOnlyAnnotations in internal/tools/tools_test.go verifying nil handling, default flipping, custom hint preservation, and pointer immutability.
• Updated internal/server/server_test.go and internal/tools/tools_test.go to test tools.ShouldSuppress with both write and destructive tools using tools.NewWriteAnnotations() and tools.NewDestructiveAnnotations().
• Updated Looker unit test suites to pass tool.GetAnnotations(nil).

[gemini-code-assist]

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