docs: pass values to strict mode flags

[FanouZeng-TT]

Description

The Strict Mode examples pass --strict without a value:

ucp-schema validate order.json --schema schema.json --request --op create --strict
ucp-schema resolve schema.json --request --op create --strict --pretty

For resolve and validate, clap defines this option as --strict <STRICT>
with true and false as the possible values. Both commands therefore exit 2
before loading their inputs:

error: a value is required for '--strict <STRICT>' but none was supplied

Passing --strict true parses successfully. The separate lint --strict flag
remains a value-less switch.

Fix: document the required value in the resolve and validate option lists,
and pass true in both Strict Mode examples.

Category (Required)

• Core Protocol: Changes to the base communication layer, global context, or breaking refactors. (Requires Technical Council approval)
• Governance/Contributing: Updates to GOVERNANCE.md, CONTRIBUTING.md, or CODEOWNERS. (Requires Governance Council approval)
• Capability: New schemas (Discovery, Cart, etc.) or extensions. (Requires Maintainer approval)
• Documentation: Updates to README, or documentations regarding schema or capabilities. (Requires Maintainer approval)
• Infrastructure: CI/CD, Linters, or build scripts. (Requires DevOps Maintainer approval)
• Maintenance: Version bumps, lockfile updates, or minor bug fixes. (Requires DevOps Maintainer approval)
• SDK: Language-specific SDK updates and releases. (Requires DevOps Maintainer approval)
• Samples / Conformance: Maintaining samples and the conformance suite. (Requires Maintainer approval)
• UCP Schema: Changes to the ucp-schema tool (resolver, linter, validator). (Requires Maintainer approval)
• Community Health (.github): Updates to templates, workflows, or org-level configs. (Requires DevOps Maintainer approval)

Related Issues

N/A

Checklist

• I have followed the Contributing Guide (including Conventional Commits title requirements and ! for breaking changes).
• I have updated the documentation (if applicable).
• My changes pass all local linting and formatting checks.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• (For Core/Capability) I have included/updated the relevant JSON schemas.
• I have regenerated Python Pydantic models by running generate_models.sh under python_sdk.

Screenshots / Logs (if applicable)

• The old resolve and validate examples exit 2 during argument parsing.
• Adding --strict true passes argument parsing and reaches input loading.
• Cargo build, the full pre-commit suite, and git diff --check passed.