Add pack validation to generate.py and CI

[breferrari]

Summary

• Add validate_pack() and validate_unique_server_names() to catch malformed packs before publishing
• Validates: required fields, name format, semver, server names/transport/command, cross-pack uniqueness
• Add --validate-only flag for local pre-commit use
• Add validate.yml workflow that runs on PRs touching src/** or scripts/generate.py
• Includes tomllib change from Replace regex TOML parsing with stdlib tomllib #10 as prerequisite

Test plan

• All 13 existing packs pass validation
• --validate-only exits without writing files
• Full generation produces byte-for-byte identical output
• CI passes on this PR

Closes #6

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds a validation phase to scripts/generate.py (and new CI workflow) so malformed packs are caught early, before registry JSON generation/publishing.

Changes:

• Add validate_pack() and validate_unique_server_names() and run them before generation, with a --validate-only mode for local/CI use.
• Switch TOML parsing to tomllib (and pin CI Python to 3.12) to support full-structure validation.
• Add a validate.yml workflow to run validation on PRs that touch src/** or scripts/generate.py.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
scripts/generate.py	Adds TOML parsing via tomllib, new validation helpers, and a --validate-only flag; runs validation before generating registry files.
.github/workflows/validate.yml	New PR workflow that runs generate.py --validate-only on relevant changes.
.github/workflows/publish.yml	Pins Python 3.12 so generate.py can rely on tomllib during publish regeneration.

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[Copilot]

validate_unique_server_names() assumes data["servers"] is a list of tables and that each element is a dict. If a pack incorrectly uses [servers] (dict) or servers = ["..."], this function will iterate wrong types and can crash with AttributeError, masking the earlier validation errors. Mirror the type checks from validate_pack() (ensure list, then ensure each server is a dict) before accessing .get().

Suggested change

	for server in data.get("servers", []):
	servers = data.get("servers")
	if servers is None:
	continue
	if not isinstance(servers, list):
	# Malformed servers section; primary validation will report this.
	continue
	for server in servers:
	if not isinstance(server, dict):
	# Skip invalid server entries to avoid masking earlier errors.
	continue

[Copilot]

servers is validated to be a list, but individual entries aren’t type-checked. If a manifest uses servers = ["foo"] (or otherwise produces a non-dict entry), server.get(...) will raise an AttributeError and crash validation instead of returning a clear error. Add an isinstance(server, dict) check inside the loop and report an error/continue when it’s not a table.

Suggested change

	for i, server in enumerate(servers):
	for i, server in enumerate(servers):
	if not isinstance(server, dict):
	errors.append(
	f"{pack_dir_name}: server #{i + 1} must be a table/object "
	f"(got {type(server).__name__})"
	)
	continue