Respect Dockerfile location form Actor.json - #27

Mirror the platform's resolution order (apify-worker ensureDockerfileExists):
the actor.json dockerfile field relative to the .actor dir (escape-checked,
warn-and-fall-through when it names nothing, invalid-format failure when
non-string), then .actor/Dockerfile, then root Dockerfile, then the bundled
platform default. The resolved path is always passed to docker.buildImage as
its dockerfile option; previously the driver relied on Docker's implicit root
Dockerfile only, so Actors with .actor/Dockerfile (like sample_actor_crawler)
could not build.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GFiYFS2Eq9833z1ruGQwUK

Rewrite comments and test titles to stand on their own (or cite
requirements/actor-driver.md) instead of referencing external design notes;
add integration tests covering runBuildInBackground's resolver wiring
(failure -> FAILED without a driver call, default -> injected Dockerfile
reaches the driver ctx without touching persisted sourceFiles, resolved ->
path passthrough); move normalizeEntryName into src/driver/tar-entry-name.ts
so the driver layer no longer imports from services.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GFiYFS2Eq9833z1ruGQwUK

…tions

requirements/test.md now names all three base images the e2e suite pulls
(python:3.11-slim joined for sample_actor_crawler); two tests asserted the
same value twice, once as a string literal and once via
DEFAULT_DOCKERFILE_NAME - the named-constant assertion stays.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GFiYFS2Eq9833z1ruGQwUK

…test placement

Document the unparseable-actor.json failure mode in the runtime spec; make
DEFAULT_DOCKERFILE_NAME the single source of truth for the injected default's
name so the collision-safety invariant is structural; drop an unneeded type
cast, a test-only re-export, and a parallel-array lookup; move the tar-entry
normalizer tests next to the module they test; cover the null-actor.json and
"../.." escape sub-guards; generalize neverStartDriver's message to every
must-not-build case it now guards.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GFiYFS2Eq9833z1ruGQwUK

The DEFAULT_DOCKERFILE_NAME doc now states the collision-safety invariant
directly; a dangling cross-reference points at driver/tar-entry-name.ts;
the spec no longer says "parsed as JSON5" twice.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GFiYFS2Eq9833z1ruGQwUK

Comments now state constraints, not rationale; the actor-driver.md section
states the observable contract (resolution order, failure messages, case
rules, log requirement) without implementation mechanics. Comment-only
change: no code, signature, or assertion lines touched.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GFiYFS2Eq9833z1ruGQwUK