feat(push): warn on npm --omit=dev + tsc build script (typescript compilation trap)

[DaveHanns]

Summary

Add a pre-upload sanity check in apify push that warns (never blocks) when the project's Dockerfile drops devDependencies before running a tsc-based build. This is one of the most common "worked locally, fails on the platform" traps for TypeScript Actors, and the platform build error (tsc: not found) gives no hint that the fix is on the Dockerfile side.

What changes

• src/commands/actors/push.ts
  • New exported helper detectOmitDevTscTrap(cwd) — pure function, returns a warning message or null. Handles both .actor/Dockerfile and ./Dockerfile, folds backslash line-continuations, matches both --omit=dev and --production, and refuses to fire on tsc-alias, tsdown, or when typescript is duplicated into dependencies.
  • The run() handler calls it right after the "Deploying Actor" log line and emits the message through the existing yellow warning() output helper (goes to stderr). Push proceeds either way.
• test/local/commands/push.test.ts
  • Nine unit cases covering positive matches and the four falsy-signal guards (typescript in both, no --omit, non-tsc build, missing Dockerfile / malformed package.json).

Design notes:

• Warning only, never a validation error — the platform's Docker build is still authoritative, and we don't want a heuristic to block anyone.
• All file access is guarded with existsSync + try/catch so a missing or unreadable Dockerfile / package.json silently no-ops.
• The tsc regex is a word-boundary-ish match (^|[\s&|;])tsc($|[\s&|;]) so we don't false-positive on tsc-alias, tsconfig-paths, tsdown, etc.

Test plan

• oxlint --type-aware clean on push.ts and push.test.ts
• tsc --noEmit -p . clean
• Standalone repro of the 9 test cases (positive/negative matrix) all pass
• Manual: run apify push in a project with a single-stage --omit=dev Dockerfile + tsc build script and confirm the yellow warning appears before the upload phase
• Manual: run apify push in a well-configured multi-stage project and confirm no warning fires

Related — coordinated remediation stack

Four defense layers, each covering a different failure mode:

• apify/actor-templates — ts-* Dockerfiles ship a multi-stage build (already in master via #592, Dec 2025). Users of apify create -t ts-* cannot hit the trap.
• This PR — apify push preflight warning when a Dockerfile has --omit=dev before npm run build that invokes tsc.
• apify/apify-cli#1261 — apify create forces --include=dev + NODE_ENV=development on the post-scaffold install, so apify run works locally.
• apify/apify-docs#2716 — docs callout on the Source-code page for the direct-docker build / search-fallback case.

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