docs: add CI pass requirement guidance

[Carlys17]

Closes #115

Description

Add a new documentation file docs/ci-pass-requirement.md that defines the CI pass requirement policy for Aegis SDK pull requests.

The document explains:

• Why CI pass status matters (evaluation impact, code quality gate, cross-environment verification)
• The CI checks table (build, tests, compat, lint, format)
• Common failure types with links to existing resolution guides
• Local verification commands (npm run check, npm run verify)
• Contributor expectations (before opening a PR, when CI fails, what happens if CI stays red)
• How to get unstuck

The README is updated with a link to the new document under the CI section.

This complements existing CI documentation (ci-resolution-workflow.md, ci-response-guide.md) by focusing on the policy and expectations rather than resolution steps.

Acceptance Criteria Coverage

• CI pass requirement guidance is added
• Guidance states that failing CI can affect evaluation
• Common failure types are listed
• Local reproduction commands are included
• Contributor fix expectations are documented
• README links to the guidance