fix: bring code into compliance with standards & cleanup documentation

[chrislyons-dev]

• add unit tests
• add quality assertions: test coverage, security checks
• documentation improvements: remove inconsistencies and inaccuracies

[Copilot]

Pull request overview

This PR enhances the codebase's quality standards by adding unit tests, implementing security scanning with secretlint and eslint-plugin-security, enabling code coverage enforcement (80% thresholds), and improving TypeScript strictness with noUncheckedIndexedAccess. The documentation has been streamlined to remove inconsistencies and clarify deployment processes.

Key changes:

• Add comprehensive unit tests for diagram generation script with 100% coverage
• Enable test coverage thresholds (80%) and TypeScript strict index access checking
• Integrate secretlint for secret detection and eslint-plugin-security for static analysis

Reviewed changes

Copilot reviewed 20 out of 83 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
vitest.config.ts	Adds 80% coverage thresholds for lines, functions, branches, and statements
tsconfig.json	Enables noUncheckedIndexedAccess for stricter array/object access
src/types/eslint-plugin-security.d.ts	Type declaration for eslint-plugin-security
src/tests/projects.test.ts	Adds null checks for array access due to noUncheckedIndexedAccess
src/scripts/*.js	Removes redundant eslint-env browser comments in favor of explicit globals
src/components/CodeBlock.tsx	Adds guards for empty arrays and undefined access
scripts/generate-diagram-images.unit.test.mjs	New comprehensive unit test suite
scripts/generate-diagram-images.mjs	Exports functions for testability and adds proper entrypoint detection
package.json	Adds security tools, updates dependencies, enhances check script
eslint.config.js	Integrates eslint-plugin-security
docs/security.md	Updates to reflect current tooling choices (secretlint, npm audit)
docs/index.md	Simplified marketing language
docs/deployment/overview.md	Clarifies CI/CD behavior
README.md	Simplified marketing language
.secretlintrc.json	Configuration for secret scanning
.husky/pre-commit	Adds secret and audit scans
.github/workflows/ci.yml	Adds security scans, enables coverage, removes continue-on-error

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[Copilot]

Typo in echo statement. Should be an emoji or a proper opening quote.

Suggested change

	echo "dY"? Running secret scan..."
	npx secretlint **/*
	echo "dY"? Running npm audit..."
	echo "🕵️ Running secret scan..."
	npx secretlint **/*
	echo "🛡️ Running npm audit..."