docs(skills): merge output-schema skill into actor-development

[patrikbraborec]

Summary

Reviewed the Actor development skills against the writing-for-agents guidance and consolidated them so there is one skill to install and one place for schema rules.

Two skills become one, and four overlapping schema references collapse into one:

 skills/
 ├── apify-actor-development/
 │   ├── SKILL.md                          # 2,221 → 935 words, rewritten
 │   └── references/
 │       ├── input-schema.md               # 191 → 550 words, rewritten from v1 spec
-│       ├── dataset-schema.md             # −209
-│       ├── output-schema.md              # −49
-│       ├── key-value-store-schema.md     # −129
+│       └── output-schemas.md             # +152, the single source of schema rules
-├── apify-generate-output-schema/
-│   └── SKILL.md                          # −415, whole skill removed
 └── apify-actorization/
     └── references/schemas-and-output.md  # repointed at output-schemas.md

Why

The two skills disagreed, so an agent following one produced schemas the other rejected:

 agent writes a schema
-  reads actor-development/references/dataset-schema.md
-    → omits `nullable`, puts `required` at one level only
-  generate-output-schema skill validates it
-    → rejects: hard rules say `nullable` everywhere, `required` at both levels
+  reads actor-development/references/output-schemas.md
+    → one set of rules, one validator, no contradiction

The same disagreement covered additionalProperties at both levels and type: string on output properties.

What changed

• Merge apify-generate-output-schema into apify-actor-development as references/output-schemas.md. The standalone skill, its marketplace entry, and its README/AGENTS.md references are removed. Its trigger branch ("generate or update schemas") now lives in the actor-development description.
• Delete the three duplicate schema references (dataset-schema.md, output-schema.md, key-value-store-schema.md).
• Rewrite input-schema.md from the v1 specification: default vs prefill vs required, editors per type, isSecret, errorMessage, resource fields, deprecated patternKey/patternValue.
• Rewrite SKILL.md: workflow steps first with checkable done-conditions, reference pointers folded into the steps, each rule stated once in positive form, command list reduced to the non-obvious entries.
• Point commands/create-actor.md and the actorization schema reference at the shared output-schemas.md. agents/AGENTS.md regenerated with scripts/generate_agents.py.

Everything else in the diff is fallout from the removal:

graph LR
    A["delete apify-generate-output-schema"] --> B["marketplace.json<br/>−16 entry"]
    A --> C["README.md<br/>−4 listing"]
    A --> D["commands/create-actor.md<br/>repoint links"]
    A --> E["agents/AGENTS.md<br/>regenerated by script"]

Loading

File	Words before	Words after
apify-actor-development/SKILL.md	2,221	935
Output-schema material (skill + 3 references)	3,406	896
input-schema.md	191	550

Breaking change

The apify-generate-output-schema plugin no longer exists. Users who installed it get the same behaviour from apify-actor-development.

Dropped and left alone, flagging for review

dropped (could not verify against current Crawlee — restore if still relevant)
├── requestHandlerTimeoutMillis gotcha
└── additionalHttpHeaders vs preNavigationHooks

dropped (restates the environment and public docs)
├── project-structure tree
└── Playwright MCP JSON config block

left alone (pre-existing, not introduced here)
├── commands/create-actor.md:60-62  → links to template files not in the repo
└── actor-json.md                   → still duplicates Structure/Example blocks and the `generatedBy` instruction