docs: launch legibility hardening

[Cubits11]

What changed

• Added community-health files: CONTRIBUTING.md, CODE_OF_CONDUCT.md, SECURITY.md, PR template, and bug/feature/research-question issue forms.
• Rewrote only the top section of README.md with the launch positioning, badges, a verified 60-second quickstart, deeper-doc links, citation pointer, and contribution pointer.
• Added draft CITATION.cff without .zenodo.json; DOI identifiers remain commented until Zenodo mints one.
• Added docs/assets/social-preview.png, generated from cc.kernel.strict.frechet_bounds for a labeled two-guardrail example.

Why

Satisfies Phase 1 local-file legibility hardening from the Launch-Hardening plan while preserving the required non-certification claim boundary.

Verification performed

make test-kernel

PYTHONPATH=src .venv/bin/pytest tests/unit/kernel -q
........................................................................ [ 50%]
........................................................................ [100%]
PYTHONPATH=src .venv/bin/pytest tests/unit/kernel/test_sensitivity.py tests/unit/kernel/test_frechet_classes.py -q
.............................................................            [100%]
PYTHONPATH=src .venv/bin/mypy src/cc/kernel --strict
Success: no issues found in 11 source files
.venv/bin/ruff check src/cc/kernel tests/unit/kernel
All checks passed!

make test-release

PYTHONPATH=src .venv/bin/pytest tests/unit/kernel -q
........................................................................ [ 50%]
........................................................................ [100%]
PYTHONPATH=src .venv/bin/pytest tests/unit/kernel/test_sensitivity.py tests/unit/kernel/test_frechet_classes.py -q
.............................................................            [100%]
PYTHONPATH=src .venv/bin/mypy src/cc/kernel --strict
Success: no issues found in 11 source files
.venv/bin/ruff check src/cc/kernel tests/unit/kernel
All checks passed!
PYTHONPATH=src .venv/bin/python examples/minimal/run_bounds.py >/dev/null
PYTHONPATH=src .venv/bin/pytest \
	  tests/integration/test_reproduce_paper.py \
	  tests/integration/test_verify_paper_artifacts.py -q
..........                                                               [100%]

README quickstart in a disposable venv with pip install -e '.[stats]'

Stacked failure is bounded by [0.00%, 10.00%]
Independence would estimate 1.00%

YAML parse check

parsed CITATION.cff
parsed .github/ISSUE_TEMPLATE/feature_request.yml
parsed .github/ISSUE_TEMPLATE/bug_report.yml
parsed .github/ISSUE_TEMPLATE/research_question.yml

Social preview check

docs/assets/social-preview.png: PNG image data, 1280 x 640, 8-bit colormap, non-interlaced
15688 bytes
bounds=[0.0, 0.1], independence=0.010000000000000002

Left for human / non-automated

• Confirm CITATION.cff author metadata before release; it was drafted from git history, not asserted as ground truth.
• Set date-released only when the actual release is published.
• Add DOI metadata only after Zenodo mints the DOI.
• Upload docs/assets/social-preview.png manually in GitHub Settings -> Social preview -> Upload image.
• Enable GitHub Discussions manually in Settings -> Features.
• Verify/enable private vulnerability reporting in repository settings.
• Apply repo description/topics separately; this environment had no gh CLI/token and the connector did not expose repository metadata editing.

Definition of Done reference

Phase 1b, 1c, 1d, and 1e local-file deliverables. Phase 1a and 1f remain manual/auth-blocked as noted above.