test(mcp): add per-tool integration coverage

[corylanou]

Summary

Adds focused integration coverage for the seven MCP tools on top of the official Go SDK migration in #1378.

• Connects the official SDK client and server with in-memory transports.
• Exercises success and error paths for every registered tool.
• Uses a temporary SQLite database synced to a real file:// replica.
• Verifies restore and reset through their filesystem and database side effects.

Investigation

The mcp_test.go added by #1378 already comprehensively covers server identity, capabilities, tool discovery, generated schemas, annotations, structured output, argument preservation, cancellation, panic recovery, and Streamable HTTP transport.

The remaining thin areas were per-tool failures, the SDK's in-process transport, and behavior against real Litestream data. This PR fills those gaps without importing changes from the other MCP branches.

Scope

In scope:

• Per-tool success and error coverage.
• Official SDK in-memory client/server transport.
• Temporary SQLite and file:// replica fixture.
• Restore-content and reset-removal assertions.

Not in scope:

• Replacing subprocess-backed MCP handlers.
• Adding MCP tools or changing tool schemas.
• Changes from sibling MCP branches.

Test Plan

go test -race -run '^TestMCPToolIntegration$' -v ./cmd/litestream/
go test -race ./cmd/litestream/
go vet ./...
pre-commit run --all-files
go test -race ./...

Related

• Stacked on refactor(mcp): migrate to the official modelcontextprotocol/go-sdk #1378
• Closes test(mcp): add an MCP server test suite #1373

[github-actions]

PR Build Metrics

✅ All clear — no issues detected

Check	Status	Summary
Binary size	✅	38.29 MB (0.0 KB / 0.00%)
Dependencies	✅	No changes
Vulnerabilities	✅	None detected
Go toolchain	✅	1.25.12 (latest)
Module graph	✅	1248 edges (0)

Binary Size

	Size	Change
Base (eb6c415)	38.29 MB
PR (4f23a3a)	38.29 MB	0.0 KB (0.00%)

Dependency Changes

No dependency changes.

govulncheck Output

=== Symbol Results ===

No vulnerabilities found.

Your code is affected by 0 vulnerabilities.
This scan also found 0 vulnerabilities in packages you import and 1
vulnerability in modules you require, but your code doesn't appear to call these
vulnerabilities.
Use '-show verbose' for more details.

Build Info

Metric	Value
Build time	51s
Go version	go1.25.12
Commit	4f23a3a

History (2 previous)

Commit	Updated	Status	Summary
cfd4f3c	2026-07-18 21:42 UTC	✅	38.27 MB (0.0 KB / 0.00%)
687f18f	2026-07-17 18:36 UTC	✅	38.27 MB (0.0 KB / 0.00%)

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_{🤖 Updated on each push.}