Examples: Standardize file headers and copyright years

[rparolin]

Parent issue: #1673

Goal

Resolve the copyright year inconsistency and apply a uniform header across all example files.

Current state

• 7 files use Copyright (c) 2024-2025 NVIDIA CORPORATION & AFFILIATES
• 4 files use Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES
• All files use SPDX-License-Identifier: Apache-2.0

Decisions needed

1. Should copyright years reflect year-of-creation to present (e.g., 2024-2025)?
2. Or should all files use a single convention regardless of creation date?

Files affected

All 25 example files listed in #1673.

[mdboom]

According to an internal discussion I had about this, the final year should only be updated when the file does. This precommit hook now handles this automatically. So maybe we can just close this bug as "will happen naturally?"