docs: Update key-value store page

[marcel-rbro]

Resolves issue #2124

---

Note

Expands Console actions section, adds an authentication tip block for API usage, and fixes wording/formatting including key length limit.

• Console usage
  • Merge and clarify instructions for viewing a store and using the Actions menu (rename/share and retention note).
  • Add explicit list of record operations at page bottom: upload, view, download (single/all), copy links, delete.
  • Reorder images around the records section.
• API
  • Convert authentication note into a :::tip block; recommend Authorization header and link to API integration docs.
• SDK docs
  • Fix wording typos: "your Actor" in JavaScript and Python sections.
  • Format {KEY} and {EXT} with backticks in Python section.
• Limits
  • Clarify phrasing of key length limit: "The maximum length for a key in a key-value store is 63 characters."

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[apify-service-account]

Preview for this PR was built for commit c369b36 and is ready at https://pr-2142.preview.docs.apify.com!

[gippy]

Thanks, one small question, but I will leave that to review from Michal :)