refactor: rename dataset to suite across codebase

[christso]

Objective

Rename dataset → suite everywhere. An eval file is a test suite (lifecycle hooks, workspace setup/teardown, execution config), not a dataset (passive input/output pairs).

Context

The field has ping-ponged: dataset → eval_set (#678) → dataset (#814). The #814 rename to dataset cited "industry conventions (Braintrust, LangSmith, DeepEval)" — but those platforms use "dataset" because their datasets really are just input/output pairs with no execution semantics. In agentv, eval files have:

• before_all / after_all lifecycle hooks
• before_each / after_each per-test hooks
• Workspace setup/teardown and pooling
• Execution config (trials, timeout, concurrency)
• Target matrix evaluation

That's a test suite, not a dataset. suite is the accurate term.

Scope

~190 occurrences across ~27 files:

Area	Files	Occurrences
packages/core/	types, orchestrator, yaml-parser, jsonl-parser, schema, validator, trace	~50
apps/cli/	artifact-writer, trace commands, pipeline, results/serve, tests	~80
apps/studio/	api, types, Sidebar, RunDetail, routes, Breadcrumbs	~110
apps/web/ (docs)	TBD	TBD
examples/	baseline JSONL files	~42 files

Wire format (JSONL results)

// Before
{"test_id":"foo","dataset":"my-eval","score":1.0,...}

// After
{"test_id":"foo","suite":"my-eval","score":1.0,...}

Backward compatibility

Same pattern as the #814 rename:

• JSONL parser accepts both suite and dataset (deprecated alias)
• Zod schema accepts both field names
• CLI --group-by dataset accepted as deprecated alias for --group-by suite
• Pipeline bench/grade read manifest.suite ?? manifest.dataset

Internal types

// Before
interface EvalTest {
  readonly dataset?: string;
}
interface EvaluationResult {
  readonly dataset?: string;
}

// After
interface EvalTest {
  readonly suite?: string;
}
interface EvaluationResult {
  readonly suite?: string;
}

Studio UI

• "Datasets" → "Suites" in headings, sidebar labels
• Route /runs/:runId/dataset/:dataset → /runs/:runId/suite/:suite
• DatasetSidebar → SuiteSidebar component rename (or keep generic)
• API endpoint /api/runs/:filename/datasets → /suites

YAML

No change needed — the top-level name field already names the suite. The dataset field on test cases becomes suite (optional grouping tag).

Acceptance Signals

• EvalTest.suite and EvaluationResult.suite replace .dataset
• JSONL output writes suite field
• JSONL parser reads both suite and dataset (backward compat)
• CLI commands use suite (--group-by suite, trace stats, etc.)
• Studio UI labels say "Suites", routes use /suite/
• Studio API endpoints renamed
• Example baseline JSONL files updated
• Docs updated on agentv.dev

Non-Goals

• Changing the YAML name field (already neutral)
• Changing the file extension (.eval.yaml is fine)
• Removing backward-compat aliases in this PR (deprecate only)

[christso]

Docs: Add "Suites" section after rename lands

After the rename is complete, add a short section to the agentv.dev docs explaining the suite concept. Suggested location: evaluation docs or a dedicated data model page.

Content (one paragraph):

Suites — An eval file is a suite: it binds test cases to execution context (workspace, hooks, targets, trials). Test cases can be inline or loaded from an external file via tests: ./cases.yaml for reuse across suites.

No need to define "dataset" as a separate concept or compare against other frameworks' terminology. Just explain what a suite is and that test cases can be externalized.