feat: fix CTE query and new features

[killme2008]

Main changes:

1. Updated dependencies to use fast MCP and simplified the server.
2. Added support for CTE queries in property results.
3. Added JSON and Markdown output formats.
4. Introduced a connection pool for GreptimeDB.
5. New tools:

Tool	Description
execute_sql	Executes SQL queries with configurable output format (CSV/JSON/Markdown) and row limits
describe_table	Returns table schema, including column names, types, and constraints
health_check	Checks database connectivity and returns server version
execute_tql	Runs TQL (PromQL-compatible) queries for time-series analysis
query_range	Performs time-window aggregations with RANGE/ALIGN syntax
explain_query	Shows execution plans for SQL or TQL queries

6. Improved security (closes Enhance security #14).
7. Desensitized query results (closes Query data desensitization #6):

id	customer_name	credit_card	cvv	bank_account	amount	ts
3	Charlie Brown	******	******	******	299.0	2024-01-03 12:00:00
2	Bob Johnson	******	******	******	149.5	2024-01-02 11:00:00
1	Alice Smith	******	******	******	99.99	2024-01-01 10:00:00

9. Added more prompt templates (closes Add prompts for support security logs anylysis #13).

[Copilot]

Pull request overview

This pull request fixes CTE (Common Table Expression) query support and adds several new features to the GreptimeDB MCP server. The main changes include fixing a spelling error ("Forbided" → "Forbidden"), adding support for WITH clauses in SQL queries, implementing new database tools (describe_table, health_check, execute_tql, query_range, explain_query), adding connection pooling, and enhancing the execute_sql tool with multiple output formats (CSV, JSON, Markdown) and row limiting.

Key changes:

• Fixed CTE queries: Added "WITH" to allowed SQL statement prefixes to enable Common Table Expressions
• New database tools: Added 5 new tools for table inspection, health checking, TQL queries, range queries, and query explanation
• Enhanced output formats: Added JSON and Markdown formatting options with proper datetime handling

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
src/greptimedb_mcp_server/utils.py	Fixed spelling error: "Forbided" → "Forbidden" in security gate error messages
src/greptimedb_mcp_server/server.py	Added connection pooling, new format_results function, 5 new tool implementations (_health_check, _describe_table, _execute_tql, _query_range, _explain_query), enhanced execute_sql with format/limit options, and refactored resource methods to use async patterns
tests/test_utils.py	Updated tests for spelling fixes, added comprehensive tests for format_value and format_results functions, added security gate tests for newly allowed operations (EXPLAIN, WITH, TQL, SHOW, DESC)
tests/test_server.py	Updated expected tool count to 6, adjusted test assertions for new CSV quoting behavior, added tests for all new tools and their parameter validation
conftest.py	Enhanced mocks to support fetchmany/fetchone, added MockConnectionPool for testing connection pooling, added mock responses for DESCRIBE, VERSION, TQL, EXPLAIN, and ALIGN queries
README.md	Updated documentation to describe new tools, features, security controls, and usage examples

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 9 comments.

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

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[killme2008]

@sunng87 @JetSquirrel

All set. Most of the code is just templates and tests, so no worries. 😄