Add copyright and licence headers to all source files

[JayVDZ]

Summary

Add a short copyright and licence header to all source code files (.cs, .razor, .ps1, etc.) to make licence terms visible at the file level.

Background

JIM is source-available under a commercial licence. While the LICENSE file in the repo root is the legal authority, per-file headers are a practical convenience — they make the licence visible when individual files are viewed out of context (e.g. copied, vendored, or browsed on GitHub).

Explicit per-file copyright headers are an industry best practice for commercially licensed software. They signal maturity, remove ambiguity, and satisfy compliance reviews in regulated environments.

Proposed Format

Use a lightweight 2-line header:

// Copyright (c) Tetron Limited. All rights reserved.
// Licensed under the Tetron Commercial License. See LICENSE file in the project root.

Adapt comment syntax for other file types (e.g. # for PowerShell, @* for Razor).

Scope

• All .cs files under src/ and test/
• All .razor files under src/JIM.Web/
• All .ps1 scripts
• Exclude auto-generated files (EF migrations, designer files, etc.)

Acceptance Criteria

• Copyright header present on all in-scope source files
• No headers on auto-generated or third-party files
• Build and tests pass with headers in place
• A .editorconfig rule or CI check enforces headers on new files going forward
• CLAUDE.md updated with copyright header guidance so new files are created with the correct header automatically