feat(mcp): add create_saved_query MCP tool

[aminghadersohi]

SUMMARY

Adds a create_saved_query mutation tool to the MCP service so AI assistants can persist SQL queries to the Saved Queries list.

New files:

• superset/commands/query/create.py — CreateSavedQueryCommand validates database access (existence + security) and creates the record via SavedQueryDAO
• superset/commands/query/exceptions.py — adds SavedQueryCreateFailedError
• superset/mcp_service/saved_query/ — new module with Pydantic request/response schemas and the @tool-decorated create_saved_query function
• superset/mcp_service/app.py — registers the tool and updates LLM instructions

Tool signature:

create_saved_query(label, sql, db_id, schema?, description?, template_parameters?)
→ { id, label, sql, db_id, schema, description, url, error? }

Follows the same mutation pattern as create_virtual_dataset.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A — backend MCP tool only.

TESTING INSTRUCTIONS

1. Start the MCP server with a running Superset instance
2. Connect an MCP client (e.g., Claude Desktop)
3. Call create_saved_query with a valid db_id, label, and sql
4. Verify the saved query appears in /savedqueryview/list/ and can be opened in SQL Lab via the returned URL
5. Call with an invalid db_id and verify a structured error is returned (no exception thrown to the client)

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

❌ Patch coverage is 35.51402% with 69 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.17%. Comparing base (5966bb1) to head (c5fa96c).

Files with missing lines	Patch %	Lines
superset/commands/query/create.py	0.00%	35 Missing ⚠️
...mcp_service/saved_query/tool/create_saved_query.py	24.32%	28 Missing ⚠️
superset/mcp_service/saved_query/schemas.py	80.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #40361      +/-   ##
==========================================
- Coverage   64.20%   64.17%   -0.03%     
==========================================
  Files        2592     2596       +4     
  Lines      139004   139111     +107     
  Branches    32273    32281       +8     
==========================================
+ Hits        89241    89279      +38     
- Misses      48231    48300      +69     
  Partials     1532     1532              

Flag	Coverage Δ
hive	39.29% <35.51%> (-0.01%)	⬇️
mysql	58.77% <35.51%> (-0.04%)	⬇️
postgres	58.85% <35.51%> (-0.04%)	⬇️
presto	40.96% <35.51%> (-0.01%)	⬇️
python	60.41% <35.51%> (-0.05%)	⬇️
sqlite	58.49% <35.51%> (-0.04%)	⬇️
unit	100.00% <ø> (ø)

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