Show an Actor's settings to its owner (fetch-actor-details section or get-actor-settings)

[DaveHanns]

Problem

fetch-actor-details shows an Actor the way Store shows it: title, description, pricing, stats, README, input schema. An agent managing its own Actor needs the settings view instead: name, title, description, seoTitle, seoDescription, categories, isPublic, isDeprecated, defaultRunOptions, standby settings, the versions with their buildTag, sourceType, and environment variable names, and the tagged builds. None of that is reachable over MCP.

Proposal

A settings section in fetch-actor-details, returned only when the caller owns the Actor, with the fields above. Environment variables are listed by name with their isSecret flag; secret values are never returned. Reuses the existing output section flags, so no new tool is needed.

If the section does not fit the Store-oriented card, the fallback is a separate read-only get-actor-settings tool, also in the actors category.

Notes

• Pairs with update-actor and update-actor-version: read, change, read back.
• The owner check reuses the account lookup push-actor does.

Part of #1412.

Draft PR: #1435