docs: align config and github workflow

[cyfyifanchen]

Summary

• Leave README.md, README.zh-CN.md, and use-cases/README.md unchanged in this PR.
• Align quickstart/configuration/security/citation docs with the current TOML-first everos init and everos server start flow.
• Move session_lock_timeout_seconds into the [memorize] section of the shipped default TOML so generated configs match the settings model.
• Update CLAUDE.md and Claude slash-command skills to use the GitHub main branch workflow instead of the old internal branch model.
• Add scripts/check_github_contributor_docs.py and wire it into make lint / make docs-check so contributor-facing docs cannot regress to the old branch/review wording.
• Add docs/github-sync.md to record the GitLab-to-GitHub sync guard: preserve GitHub-only contributor, workflow, template, and Claude skill files during future exports/overwrites.

Why

The codebase is already TOML-first and requires provider base_url values at runtime, but some non-README docs still described outdated config behavior or stale package metadata.

Separately, contributor guidance copied from the internal workflow still referenced non-existent public branches and review terminology. That does not affect normal users, but it can mislead community contributors and automated Claude Code skills.

This PR also records the future sync rule explicitly: when refreshing GitHub from GitLab/internal exports, do not overwrite the GitHub-only contributor docs, workflows, templates, or Claude skills that encode the public main branch workflow.

Validation

• make docs-check
• make lint
• uv run python scripts/check_pr_title.py "docs: align config and github workflow"
• uv run python scripts/check_docs.py
• uv run python scripts/check_repo_assets.py
• uv run python scripts/check_deprecated_names.py
• uv run python scripts/check_github_contributor_docs.py
• uv run pytest tests/unit/test_config/test_settings.py tests/unit/test_entrypoints/test_cli/test_init_command.py -q
• uv run pytest tests/unit/test_component/test_llm/test_client.py tests/unit/test_component/test_llm/test_factory.py tests/unit/test_component/test_embedding/test_factory.py tests/unit/test_component/test_rerank/test_factory.py -q
• uv run pytest tests/unit/test_scripts/test_check_github_contributor_docs.py tests/unit/test_scripts/test_check_deprecated_names.py -q
• uv run ruff check scripts/check_github_contributor_docs.py tests/unit/test_scripts/test_check_github_contributor_docs.py
• uv run ruff format --check scripts/check_github_contributor_docs.py tests/unit/test_scripts/test_check_github_contributor_docs.py
• uv run ruff check src tests
• uv run python scripts/dump_openapi.py --check
• uv run python scripts/check_datetime_discipline.py
• uv run ruff format --check src tests
• uv run lint-imports