feat: implement -p flag for print statistics

[dlevy-msft-sql]

Summary

Adds support for the -p flag which prints performance statistics after each batch execution, improving compatibility with legacy ODBC sqlcmd.

Changes

• cmd/sqlcmd/sqlcmd.go: Added -p flag parsing with validation for values 0 or 1
• pkg/sqlcmd/sqlcmd.go: Added timing measurement and printStatistics() method
• pkg/sqlcmd/sqlcmd_test.go: Added unit tests for standard format, colon format, and disabled scenarios
• README.md: Added documentation with usage example

Usage

# Standard format (default)
sqlcmd -S server -Q "SELECT 1" -p

# Colon-separated format
sqlcmd -S server -Q "SELECT 1" -p1

Output Formats

Standard format (-p or -p0)

Network packet size (bytes): 4096
1 xact[s]:
Clock Time (ms.): total         5  avg   5.00 (200.00 xacts per sec.)

Colon-separated format (-p1)

4096:1:5:5.00:200.00

Testing

• All new tests pass
• golangci-lint run passes
• Build succeeds

[Copilot]

Pull request overview

This PR adds support for a -p flag that prints per-batch performance statistics, improving compatibility with legacy ODBC sqlcmd and documenting the feature and its formats.

Changes:

• Extend the Sqlcmd engine with a PrintStatistics option and a printStatistics helper that measures batch execution time and prints statistics in standard or colon-separated format.
• Wire the new -p/--print-statistics flag through the CLI argument parsing pipeline, including normalization and propagation into the Sqlcmd instance.
• Add unit tests for the statistics output formats and disabled behavior, and document usage and sample output in the README.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
pkg/sqlcmd/sqlcmd.go	Adds PrintStatistics support, measures batch duration in runQuery, and implements printStatistics for both human-readable and colon-separated output.
pkg/sqlcmd/sqlcmd_test.go	Adds tests that verify standard-format output, colon-separated output, and the disabled case when PrintStatistics is nil.
cmd/sqlcmd/sqlcmd.go	Introduces the -p/--print-statistics CLI flag, integrates it into argument parsing, normalization, and run, and passes the option into the Sqlcmd core.
README.md	Documents the new -p behavior and shows an example of the standard statistics output format.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.