sshdconfig: add tracing and update constants

[tgauth]

PR Summary

• add json tracing to sshdconfig (based on registry implementation)
• update consts lists in metadata.rs and add related tests to tree-sitter grammar and parser

[Copilot]

Pull Request Overview

This PR adds JSON tracing functionality to the sshdconfig tool and updates SSH configuration constants and parsing logic. The changes implement structured logging similar to the registry implementation and expand the list of supported SSH configuration keywords.

• Adds JSON-formatted tracing with stderr output for better observability
• Updates SSH keyword constants to include more multi-argument and repeatable keywords
• Enhances parser validation and adds support for quoted strings with spaces

Reviewed Changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
sshdconfig/src/main.rs	Adds tracing initialization and structured logging with debug statements
sshdconfig/src/util.rs	Implements enable_tracing() function for JSON-formatted logging setup
sshdconfig/src/parser.rs	Adds debug logging, multi-arg validation, and string trimming
sshdconfig/src/metadata.rs	Expands MULTI_ARG_KEYWORDS and REPEATABLE_KEYWORDS constants
sshdconfig/src/get.rs	Adds debug logging to get operations
sshdconfig/Cargo.toml	Updates tracing-subscriber with additional features
sshdconfig/locales/en-us.toml	Adds new error messages and reorganizes existing ones
sshdconfig/tests/defaultshell.tests.ps1	Updates tests to parse JSON tracing output
tree-sitter-ssh-server-config/test/corpus/valid_expressions.txt	Adds test case for repeatable keyword parsing

[SteveL-MSFT]

I noticed in local builds this message:

Building tree-sitter-ssh-server-config ... for current
Warning: rule empty_line is just a `seq` or `choice` rule with a single element. This is unnecessary.

Do you want to fix that in this PR as well?

[SteveL-MSFT]

should i18n all strings