feat(appkit): agent eval framework, judge, mlflow connector (stack 2/5)

[MarioCadenas]

Stack 2/5 · targets pr/agent-evals-1-tracing (review after #1).

The core eval framework, plus LLM-as-judge and the MLflow REST connector.

• Authoring (defineEval): drive an agent over HTTP against a running app; assert with t.succeeded(), t.calledTool(), t.check(value, matcher) (includes/equals/matches). Gate-by-default, .soft() to demote.
• Native MLflow Evaluation runs: a run tagged genai_evaluate; each turn's trace links via mlflow.sourceRun; per-assertion feedback written via the assessments REST API.
• LLM-as-judge (t.judge.factuality/closedQA/custom) via autoevals → a Databricks serving endpoint.
• connectors/mlflow: MlflowClient (host/token, post/postResult, serving URL) + resolveDatabricksAuth/resolveWorkspaceClient (OAuth from a CLI profile — no hand-set PAT). Extracted so both evals and future callers share the REST/auth layer.
• appkit agent eval CLI.

Squashed history note: contains the framework, judge, and connector-extraction commits.

[github-actions]

📦 Bundle size report

Compared against bundle-size-baseline.json (main).

@databricks/appkit

npm tarball (packed): 1.1 MB (+43 KB) — gzipped download (dist + bin; excludes release-only docs/NOTICE).

dist	raw	gzip
JS (runtime)	1.1 MB (+35 KB)	397 KB (+15 KB)
Type declarations	406 KB (+20 KB)	145 KB (+9.3 KB)
Source maps	2.2 MB (+72 KB)	745 KB (+30 KB)
Other	11 KB	3.7 KB
Total	3.7 MB (+128 KB)	1.3 MB (+54 KB)

Per-entry composition (own code — deps external (as shipped))

Entry	Initial (gz)	Lazy (gz)	Total (gz)	node_modules (min)	Own code (min)
.	95 KB (+1 B)	2.5 KB	98 KB (+1 B)	external	313 KB
./beta	81 KB (+4.5 KB)	455 B (-1 B)	81 KB (+4.5 KB)	external	242 KB (+12 KB)
./testing	17 KB	0 B	17 KB	external	51 KB
./tsdown	520 B	0 B	520 B	external	813 B
./type-generator	23 KB	0 B	23 KB	external	65 KB

Chunks:

Entry	Chunk	Load	Size (gz)
.	index.js	initial	91 KB
.	utils.js	initial	4.0 KB
.	remote-tunnel-manager.js	lazy	2.5 KB
./beta	beta.js	initial	65 KB
./beta	stream-manager.js	initial	5.8 KB
./beta	wide-event-emitter.js	initial	3.2 KB
./beta	databricks.js	initial	3.2 KB
./beta	configuration.js	initial	2.1 KB
./beta	service-context.js	initial	1.3 KB
./beta	client.js	initial	434 B
./beta	client-options.js	initial	219 B
./beta	supervisor-api.js	lazy	192 B
./beta	databricks.js	lazy	141 B
./beta	index.js	lazy	122 B
./testing	index.js	initial	17 KB
./tsdown	index.js	initial	520 B
./type-generator	index.js	initial	23 KB

@databricks/appkit-ui

npm tarball (packed): 350 KB (-4 B) — gzipped download (dist + bin; excludes release-only docs/NOTICE).

dist	raw	gzip
JS (runtime)	395 KB	132 KB
Type declarations	229 KB	84 KB (-1 B)
Source maps	766 KB	253 KB
CSS	16 KB	3.2 KB
Total	1.4 MB	473 KB (-1 B)

Per-entry composition (consumer bundle — deps bundled, peerDeps external)

Entry	Initial (gz)	Lazy (gz)	Total (gz)	node_modules (min)	Own code (min)
./js	5.3 KB	49 KB	55 KB	208 KB	14 KB
./js/beta	20 B	0 B	20 B	0 B	0 B
./react	432 KB	49 KB	481 KB	1.3 MB	177 KB
./react/beta	1.0 KB	0 B	1.0 KB	0 B	1.9 KB

Chunks:

Entry	Chunk	Load	Size (gz)
./js	index.js	initial	5.2 KB
./js	chunk	initial	120 B
./js	apache-arrow	lazy	49 KB
./js/beta	beta.js	initial	20 B
./react	index.js	initial	430 KB
./react	tslib	initial	2.1 KB
./react	apache-arrow	lazy	49 KB
./react/beta	beta.js	initial	1.0 KB

[github-actions]

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📦 Try this PR's app template

Scaffolds a new app from this PR's SDK build. Run it in any folder (requires the GitHub CLI — gh auth login — and the Databricks CLI):

gh run download 33763255268 -R databricks/appkit -n appkit-template-0.71.0-pr.97064b1-pr-agent-evals-2-framework-478 -D appkit-pr-478 \
  && unzip -o "appkit-pr-478/appkit-template-0.71.0-pr.97064b1-pr-agent-evals-2-framework-478.zip" -d "appkit-pr-478" \
  && databricks apps init --template "appkit-pr-478"

The template pins @databricks/appkit and @databricks/appkit-ui to tarballs built from this branch, so the scaffolded app runs against this PR's code.