docs: add shared-store rate-limit examples to OWASP instructions and UpstashRedisCache to LangChain caching 🤖🤖🤖

[CahidArda]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• I have read and followed the Guidance for submissions involving paid services.
• My contribution adds a new instruction, prompt, agent, skill, workflow, or canvas extension file in the correct directory. (N/A — updates existing files)
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, agent, skill, workflow, or canvas extension with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.
• I am targeting the main branch for this pull request.

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Description

Adds shared-store rate-limit examples (rate-limit-redis / @upstash/ratelimit) next to the existing express-rate-limit snippets in security-and-owasp.instructions.md (AU5, AP1), and one bullet in the Caching section of langchain-python.instructions.md naming LangChain's UpstashRedisCache among InMemoryCache/SQLiteCache/RedisCache. Existing names and examples are unchanged.

Neither edit touches a frontmatter description, so npm start produces no generated-file diff.

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Type of Contribution

• New instruction file.
• New prompt file.
• New agent file.
• New plugin.
• New skill file.
• New agentic workflow.
• New canvas extension.
• Update to existing instruction, prompt, agent, plugin, skill, workflow, or canvas extension.
• Other (please specify):

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Additional Notes

Affiliation disclosure: I work at Upstash, the company that operates the services named in these edits. Upstash is added as one option next to the existing tools, not in place of them, per Discussion #968.

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

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🔒 PR Risk Scan Results

Scanned 2 changed file(s).

Severity	Count
🔴 High	0
🟠 Medium	0
ℹ️ Info	0

✅ No matching risk patterns were detected in changed files.

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