docs: translate StreamSQL documentation and update dependencies

[faiz-muttaqin]

What changed

• Translated developer-facing comments, English documentation, function guides, and examples into technical English.
• Improved terminology for aggregation, analytic functions, windows, CEP, expressions, and SQL processing.
• Updated the module to Go 1.26.5 and upgraded compatible dependencies.
• Adjusted a logger test for Go 1.26 vet compatibility.

Why

StreamSQL’s English source documentation still contained extensive Chinese explanatory text. This change makes the implementation and examples easier for global contributors to understand while keeping SQL behavior and test contracts stable.

Impact

• Developer-facing documentation becomes consistently available in English.
• The minimum Go version becomes Go 1.26.5.
• SQL values, fixtures, test expectations, identifiers, and the intentional Chinese README edition remain unchanged.

Validation

• Ran gofmt on modified Go files.
• go test ./...
• go mod verify

All commits include the required DCO sign-off.