docs(apify-actor-development): include agent-bases AGENTS.md when scaffolding without the CLI

[DaveHanns]

Rationale

The apify/actor-templates repo carries per-language agent-bases/{lang}.AGENTS.md guidance files that every template inherits from. apify create composes these into the scaffold automatically, but agents that bypass the CLI and fetch template files directly (via raw GitHub URLs or the manifest's archiveUrl) silently miss the file — losing the language-specific Actor guidance they'd otherwise get for free.

This adds a short subsection under ## Template selection in the apify-actor-development skill that names the convention and points at the raw URL to fetch alongside the template files.

Added content

When scaffolding without the CLI, also fetch agent-bases/{lang}.AGENTS.md

The apify/actor-templates repo carries per-language guidance files (js.AGENTS.md, ts.AGENTS.md, python.AGENTS.md) under agent-bases/ that all templates inherit from. apify create composes these into the scaffold automatically. When you bypass the CLI and fetch template files directly (via the raw GitHub URLs or the manifest's archiveUrl), the composition doesn't happen — so also fetch https://raw.githubusercontent.com/apify/actor-templates/master/agent-bases/{lang}.AGENTS.md for your language and drop it into the project root alongside the template files. See the actor-templates README for the full convention.

Surfaced during an evaluation of Apify surfaces for agent-driven Actor development.