QVAC-17434 chore[bc]: migrate SDK plugins to new addon constructor shape

[donriddo]

Note: be concise and prefer bullet points.

🎯 What problem does this PR solve?

• The embed, LLM, and diffusion addon interface refactors landed on main, but the matching SDK plugin migration did not.
• The built-in SDK plugins were still instantiating those addons with the old loader-based constructor shape, so the SDK branch was out of sync with the published addon APIs.
• The SDK also still carried old loader/model-path plumbing that no longer matched the addon contract.

📝 How does it solve it?

• Migrate the built-in llamacpp-completion, llamacpp-embedding, and sdcpp-generation plugins to the new single-argument addon constructor: { files, config, logger, opts }.
• Return { model } from migrated plugins and remove the old loader adapter path that is no longer used by those addons.
• Add packages/sdk/server/utils/expand-gguf-shards.ts so a single sharded GGUF path expands into the ordered .tensors.txt + shard list expected by the addon files.model contract.
• Remove obsolete SDK plumbing (FilesystemDL, loader-adapter, model-path) and bump the SDK's addon dependency versions to the refactored releases.
• Update unit coverage for shard expansion and adjust affected plugin tests to the new return shape.

🧪 How was it tested?

• On Linux, ran bun run build in packages/sdk.
• On Linux, ran bun run test:unit in packages/sdk.
• Added expand-gguf-shards.test.ts coverage for sharded and non-sharded paths, nested and relative paths, 1-of-1 shards, and Windows-style separators.
• Ran bun install --frozen-lockfile after the dependency bumps to confirm the lockfile resolves cleanly.

💥 Breaking Changes

• PluginModelResult no longer includes loader.
• Built-in SDK consumers are unaffected, but custom plugin authors returning loader must update to return only model.

BEFORE:

export const myPlugin = definePlugin({
  // ...
  createModel(params: CreateModelParams): PluginModelResult {
    return { model, loader: null };
  },
});

AFTER:

export const myPlugin = definePlugin({
  // ...
  createModel(params: CreateModelParams): PluginModelResult {
    return { model };
  },
});

[Proletter]

review

[github-actions]

Tier-based Approval Status

**PR Tier:** TIER1

**Current Status:** ✅ APPROVED

**Requirements:**
- 1 Team Member approval ✅ (1/1)
- 1 Team Lead OR Management approval ✅ (1/1)



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*This comment is automatically updated when reviews change.*

[Proletter]

review

[tamer-hassan-tether]

/review

[tamer-hassan-tether]

/review

[yuranich]

/review

[simon-iribarren]

Root cause of the SDK unit test failure

Looking at run 24882238163, the failing step is Run unit tests with this crash (not a test assertion failure):

1 | module.exports = require.addon()
                             ^
TypeError: require.addon is not a function. (In 'require.addon()', 'require.addon' is undefined)
      at <anonymous> (.../node_modules/bare-type/binding.js:1:26)
      at <anonymous> (.../node_modules/bare-type/index.js:1:7)
      at <anonymous> (.../node_modules/bare-inspect/index.js:2:7)
      at <anonymous> (.../node_modules/bare-assert/index.js:1:7)
      at <anonymous> (.../node_modules/bare-crypto/lib/constants.js:1:9)

Bun v1.3.13 (Linux x64)

require.addon() is a Bare-only runtime API. Unit tests run under Bun, so any test file that transitively imports bare-crypto crashes while loading.

Why this regressed now

It's caused by commit 991686bb ("route expand-gguf-shards import through server/utils barrel"):

• packages/sdk/server/utils/index.ts now re-exports expand-gguf-shards, alongside ./checksum and ./formatting — both of which do import crypto from "bare-crypto".

• packages/sdk/test/unit/expand-gguf-shards.test.ts was changed from

  import { expandGGUFIntoShards } from "@/server/utils/expand-gguf-shards";

  to

  import { expandGGUFIntoShards } from "@/server/utils";

  Going through the barrel pulls in every sibling module, including checksum.ts and formatting.ts, which drags bare-crypto → bare-assert → bare-inspect → bare-type into the Bun process and blows up on require.addon().

The earlier successful check (sdk) run on the prior PR head (2dad6294) did not have this issue because the test imported the module directly.

Suggested fix

Revert the test's import to the direct file path:

import { expandGGUFIntoShards } from "@/server/utils/expand-gguf-shards";

The plugin imports (llamacpp-completion/plugin.ts, llamacpp-embedding/plugin.ts) going through the barrel are fine — those files only run under Bare, where bare-crypto works. It's specifically the unit test that cannot traverse the barrel.

As a broader cleanup (optional, separate PR), server/utils/index.ts shouldn't re-export Bare-coupled modules (checksum, formatting) if any non-Bare consumer might pull the barrel.

Dismissing my own approval — CI is failing due to the barrel import change in 991686b; PR needs the fix before merging.

[yuranich]

/review