Update licenses and add third party notice

[pzelasko]

Summary

• add a top-level THIRD-PARTY-NOTICES covering all 330 third-party dependencies, grouping package/version lists by applicable license and including the full license terms
• retain notices for incorporated or adapted source code inline, and complete missing inline copyright, license, and source attributions in 11 affected files
• add SPDX-License-Identifier: Apache-2.0 and normalize the NVIDIA entity to NVIDIA CORPORATION & AFFILIATES in all 1,651 in-scope source headers while preserving every existing year
• add the requested 2019-2026 NVIDIA copyright line to the beginning of LICENSE
• add a Signing Your Work section to CONTRIBUTING.md with the complete verbatim DCO 1.1 text and sign-off instructions
• correct the Daily client SPDX identifier from BSD 2-Clause License to BSD-2-Clause

The changes are split into focused, signed-off commits so the dependency notices, bulk source-header migration, LICENSE update, DCO text, SPDX correction, and inline attribution fixes can be reviewed independently.

Validation

• pre-commit run --from-ref origin/main --to-ref HEAD
• git diff --check origin/main..HEAD
• verified that THIRD-PARTY-NOTICES contains 30 full license-text sections and that all 330 dependencies are covered by at least one applicable license section
• verified that the notice contains no internal review, source-analysis, or construction-methodology language
• audited all 1,651 target files: each contains the required NVIDIA entity and Apache-2.0 SPDX identifier
• verified the first line of LICENSE, the Signing Your Work section, and the corrected BSD-2-Clause identifier
• verified that every commit contains the required Signed-off-by trailer

Unit tests were not run because this PR changes licensing metadata, comments, and documentation only.