feat(insights): migrate Analyst context to Ethos

[aleckhoury]

Summary

This change applies the direct Agent Spec-to-Ethos rename across Analyst inputs, profiles, jobs, prompts, tests, and documentation.
It preserves the Analyst's prior fallback, benchmark, preflight, and prompt behavior.
This child PR targets the authoritative rename PR.

Changes

• Rename the Analyst CLI, profile, job, and runtime inputs to Ethos terminology.
• Replace the preferred artifact name with ETHOS.md while retaining the README.md fallback.
• Preserve existing benchmark policy handling and the divergence prompt contract.
• Remove prior runtime names and compatibility aliases.
• Update existing tests and documentation without adding validation or source-label behavior.

Type of Change

• Code change (feature, bug fix, or refactor)
• Code change with documentation updates
• Documentation only
• Contributor tooling or automation
• CI, build, or test infrastructure

Quality Gates

• Tests added or updated for changed behavior
• Existing tests cover changed behavior — justification: existing Analyst tests use the renamed fields, flags, paths, and prompt input.
• Tests not applicable — justification:
• Documentation updated for user-visible behavior
• Documentation not applicable — justification:

Verification

• Pull request title follows the repository's Conventional Commit format
• Every commit includes an appropriate Signed-off-by: trailer
• uv run pre-commit run -a passes, or any blocked checks are identified below
• Targeted tests pass, or tests are marked not applicable above
• No secrets, API keys, or credentials are included

Targeted validation:

• uv run --frozen pytest plugins/nemo-insights/tests -q: 617 passed, 1 skipped.
• uv run --frozen ruff check plugins/nemo-insights: passed.
• uv run --frozen ruff format --check plugins/nemo-insights: 90 files already formatted.
• Targeted uv run --frozen ty check across changed source files: passed.
• PR-scoped uv run pre-commit run --files: passed.
• make docs-broken-links: passed.
• git diff --check: passed.
• uv run pre-commit run -a: core checks passed. The Helm hook modified unrelated generated documentation, and this worktree lacks Studio's lint-staged binary.
• make docs-check: blocked because this worktree contains Git LFS pointer files.

[github-actions]

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