chore: add dual license (Apache-2.0 code + CC-BY-4.0 docs)

[kambleakash0]

User description

What

Adds the license the pre-publication audit flagged as missing (a public repo with no LICENSE defaults to all-rights-reserved, which conflicts with the open-for-contributors intent).

• LICENSE — Apache-2.0, covering code + configuration (matches the Mistral-7B base and Granite Guardian, both Apache-2.0).
• LICENSE-docs — CC-BY-4.0, covering the prose deliverables (docs/, and the narrative write-ups under reports/ including reports/safestack_report.md).
• README — a License section documenting the split.

Third-party datasets/models keep their own upstream licenses (see RESPONSIBLE_USE.md and the manifests).

Pre-publication audit (context)

A 5-dimension audit ran before this: sanitized data (all harmful sources hash-only), notebook outputs (no harmful generations, no secrets), secrets across the full 116-commit history (clean), private-artifact/weight leakage (none ever committed), and responsible-use docs (coherent). All 18 private HF adapter repos confirmed gated (401 unauthenticated). This LICENSE was the only remaining gap.

Closes #201

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PR Type

Other, Documentation

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Description

• Add Apache-2.0 licensing for code and configuration.

• License prose deliverables under CC-BY-4.0.

• Document licensing boundaries and upstream license exceptions.

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File Walkthrough

	Relevant files
Licensing	LICENSE Add Apache-2.0 license for code and configuration                LICENSE Add the Apache License 2.0 text, including copyright and patent grants, redistribution conditions, and liability disclaimers. Include a copyright notice for Akash Kamble dated 2026. +201/-0  LICENSE-docs Define prose licensing scope and third-party exceptions    LICENSE-docs Add a CC-BY-4.0 notice covering docs/ and narrative write-ups under reports/. Explicitly retain Apache-2.0 coverage for code, configuration, notebooks, and machine-readable report artifacts. Summarize attribution requirements and link to the full legal text and human-readable license summary. Clarify that third-party materials retain upstream licenses, referencing RESPONSIBLE_USE.md and dataset manifests. +32/-0
Documentation	README.md Document license split and upstream licensing references  README.md Add a License section linking to LICENSE and LICENSE-docs. Explain the split between Apache-2.0 code/configuration and CC-BY-4.0 prose deliverables. Note upstream licensing for third-party datasets, models, and tools. +9/-0

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[github-actions]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis ✅ 201 - PR Code Verified Compliant requirements: Add Apache-2.0 licensing for repository code. Add CC-BY-4.0 licensing for prose deliverables in docs/ and reports/. Add a README License section documenting the licensing split. Requires further human verification: Confirm these licensing changes are merged before the repository is made public.

⏱️ Estimated effort to review: 1 🔵⚪⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ No major issues detected