fix(extensions): include emitted events in ext:info output

[Noxtimo]

Description

In ext:info, extension specifications declaring custom Eventarc events under spec.events were omitted from both Markdown and terminal output formats. This caused automated README documentation generated via firebase ext:info --markdown to lack emitted event documentation. This change formats and displays the Events Emitted: section whenever spec.events is present on the extension specification.

Fixes #8209

Scenarios Tested

• Added unit tests in src/commands/ext-info.spec.ts verifying Events Emitted: header and event details are rendered for --markdown and terminal modes.
• Verified event types render cleanly when descriptions are missing or empty without trailing colons.
• Verified no event section is rendered when spec.events is omitted or empty.
• Ran npx mocha src/commands/ext-info.spec.ts (4 passing).
• Ran npx mocha src/extensions/*.spec.ts (401 passing).
• Ran npm run test:compile (clean exit).
• Ran npx prettier --check and npx eslint on modified files.

Sample Commands

• firebase ext:info firestore-bigquery-export --markdown
• firebase ext:info ./my-extension

[gemini-code-assist]

Code Review

This pull request updates the ext:info command to include emitted events in its output, accompanied by comprehensive unit tests and a changelog entry. The feedback suggests two improvements: explicitly verifying that spec.events is an array using Array.isArray() to prevent runtime errors, and refactoring the event string construction to use a single conditional template literal instead of string concatenation for better readability.

[gemini-code-assist]

To prevent potential runtime errors or unexpected output (such as printing * undefined) if spec.events is malformed (e.g., parsed as a string or object instead of an array), we should explicitly verify that spec.events is an array using Array.isArray(), similar to how spec.params is checked on line 75.

Suggested change

	if (spec.events && spec.events.length > 0) {
	if (spec.events && Array.isArray(spec.events) && spec.events.length > 0) {

References

1. Use strict null checks and handle undefined/null explicitly. ^(link)

[gemini-code-assist]

Using string concatenation (+) with template literals can be less readable. We can simplify this by using a single template literal with a conditional expression, or by splitting it into a cleaner conditional template literal.

Suggested change

	lines.push(`* ${event.type}` + (event.description ? `: ${event.description}` : ""));
	lines.push(event.description ? `* ${event.type}: ${event.description}` : `* ${event.type}`);