refactor(schema): defer builder validation to build

[johanpel]

Description

Now that a signficant portion of the YAML path has been trodden, clean some collateral slop up and solve #401 as well.

Migrates schema, FSM, and resource builders to infallible with_* setters. Builders preserve declaration order and validate duplicate or empty names during the fallible build() step.

Updates YAML lowering, code generation, and workspace callers. Removes obsolete fallible setters and unused builder APIs.

Related Issues

Closes #401.

Written by Codex.

[coderabbitai]

📝 Walkthrough

Walkthrough

The schema builder APIs now use infallible with_* chaining and defer duplicate and annotation validation to build(). FSM, resource, and YAML lowering paths propagate the revised errors and diagnostics, while tests and examples update their builder call sites.

Changes

Builder and lowering refactor

Layer / File(s)	Summary
Deferred schema validation crates/schema/src/builder/*	Schema, entity, event, record, and annotation builders now use vector-backed storage, infallible with_* methods, and fallible validation during build().
FSM and resource build behavior crates/fsm/src/builder.rs, crates/resource/src/builder.rs	FSM construction adopts the revised builders and returns the first topology error; resource capacity validation moves to build() and aggregated resource errors are removed.
Diagnostic-aware YAML lowering crates/yaml/src/lib.rs, crates/yaml/src/lower.rs, crates/yaml/tests/diagnostics.rs	YAML lowering returns Option<Schema>, converts builder failures into diagnostics, and stops parsing when schema construction fails.
Updated builder call sites crates/constraints/*, crates/fsm/tests/*, crates/instrumentation-build/*, crates/ref-*/tests/*, crates/resource/tests/*, crates/schema/src/test_utils.rs, crates/schema/src/visitor.rs	Tests, examples, and helper constructors switch from try_* methods to with_* chaining with final build-result handling.

Estimated code review effort: 5 (Critical) | ~120 minutes

Possibly related PRs

• rapidsai/quent#399: Modifies the same FSM entity-building and error-reporting path.
• rapidsai/quent#360: Updates related schema and annotation builder call sites.
• rapidsai/quent#270: Introduces the YAML lowering path updated here.

Suggested reviewers: mbrobbel, dhruv9vats

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly matches the main change: moving builder validation to the build step.
Description check	✅ Passed	The description covers the refactor and linked issue, but omits the Testing section and Screenshots section from the template.
Linked Issues check	✅ Passed	The changes implement #401 by making schema-related builder setters infallible and deferring validation to build().
Out of Scope Changes check	✅ Passed	The YAML, codegen, and caller updates are part of the stated refactor scope, with no clear unrelated changes.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

crates/schema/src/builder/entity.rs (1)

59-72: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Add regression tests for deferred event validation.

Please cover duplicate event names being rejected by build() and distinct events retaining declaration order. The shown test only exercises the empty-events case, leaving the primary behavior changed here unverified.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/schema/src/builder/entity.rs` around lines 59 - 72, Add regression
tests for EntityBuilder::build covering duplicate event names returning the
expected BuilderError and distinct events preserving their declaration order in
the resulting Entity. Keep the existing empty-events test, and construct events
through the same test helpers or public APIs already used in the entity builder
tests.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@crates/schema/src/builder/entity.rs`:
- Around line 59-72: Add regression tests for EntityBuilder::build covering
duplicate event names returning the expected BuilderError and distinct events
preserving their declaration order in the resulting Entity. Keep the existing
empty-events test, and construct events through the same test helpers or public
APIs already used in the entity builder tests.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: QUIET

Plan: Enterprise

Run ID: dcad4fd0-7890-4a88-bbfb-96b122a35bd3

📥 Commits

Reviewing files that changed from the base of the PR and between ead6d6d and 5f40c82.

📒 Files selected for processing (1)

• crates/schema/src/builder/entity.rs

[johanpel]

/merge