Add support for forcing re-build of Images

[ehdr]

Note

Adds force-build support (via MODAL_FORCE_BUILD and modal.toml force_build) and new optional forceBuild params across image APIs in JS/Go; deprecates JS secret arg; breaking: Go image methods now take Params structs.

• Config/Profile
  • Read global force-build from MODAL_FORCE_BUILD env and force_build in ~/.modal.toml (modal-go/config.go, modal-js/src/config.ts).
• Go SDK
  • Image APIs accept new params:
    • Images.FromRegistry(tag, *ImageFromRegistryParams) (adds ForceBuild and optional Secret).
    • Images.FromAwsEcr(tag, secret, *ImageFromAwsEcrParams) and Images.FromGcpArtifactRegistry(tag, secret, *ImageFromGcpArtifactRegistryParams) (add ForceBuild).
    • Image.Build(ctx, app, *ImageBuildParams) (adds ForceBuild).
  • Force-build is computed from profile/env, image-level, layer-level, and build params; propagates across layers.
  • Call sites updated (Sandbox.Create, examples, tests).
• JS SDK
  • Add optional forceBuild to images.fromRegistry, images.fromAwsEcr, images.fromGcpArtifactRegistry, and Image.build.
  • Add secret to ImageFromRegistryParams; deprecate separate secret arg in fromRegistry(); update App.imageFromRegistry()/static helpers.
  • Implement force-build aggregation/propagation (profile/env → image → layers → build param).
  • Expose new types in index.ts.
• Tests/Examples
  • Add/adjust tests to cover force-build from params, env, and propagation; update examples to new method signatures.
• Changelog
  • Document new env/config options, JS additions, deprecation, and Go breaking changes.

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[freider]

Hmm.So annoying with the non-optionality of arguments in Go, feels like this isn't something that should have to be expressed in 99% of cases. Is the idea that nil should mean "defer to global setting" as opposed to false which is "don't force build even if global setting says to?"?

[ehdr]

Yes, it would be the following:

• Images.FromRegistry("alpine:3.21", nil) - will use an empty ImageFromRegistryParams, where all fields are initialized to their zero values, so ForceBuild: false
• Images.FromRegistry("alpine:3.21", &modal.ImageFromRegistryParams{ForceBuild: false}) - equivalent but more explicitly ForceBuild: false.
• Images.FromRegistry("alpine:3.21", &modal.ImageFromRegistryParams{ForceBuild: true}) - ForceBuild: true, obvs.

[thomasjpfan]

Besides the merge conflicts, I'm okay with this for a breaking 0.7 update.

[thomasjpfan]

Being able to force build everything feels like a DevX gotcha, that I'm not sure how to resolve.

If a developer force builds a registry image, then sandbox in production using that image with DockerfileCommands will run into higher latency because that image will be rebuilt.