feat(mermaid): classDiagram + requirementDiagram emitters + CLI flags (v0.10.x M3)

[avrabe]

Summary

• Adds emit_class_diagram(instance, opts) to spar-mermaid: one Mermaid class block per distinct AADL component type, with category stereotypes (<<system>>, <<thread>>, etc.) and feature attributes (+in data port foo). Respects categories / max_depth filters from MermaidOptions.
• Adds emit_requirement_diagram(yaml_path) to spar-mermaid: line-oriented parser (no new deps — mirrors the pattern in spar-sysml2) reads rivet requirements.yaml and emits Mermaid requirementDiagram blocks with satisfies/verifies/derives edges. Non-requirement types (e.g. design-decision) are silently skipped.
• Extends spar emit --format to accept mermaid (default, flowchart, unchanged), mermaid-class (calls emit_class_diagram), and mermaid-req (calls emit_requirement_diagram against artifacts/requirements.yaml — no AADL files or --root needed).
• 6 new library unit tests + 2 new CLI integration tests; all green.
• Appends REQ-MERMAID-CLASS-001, REQ-MERMAID-REQ-001, TEST-MERMAID-CLASS, TEST-MERMAID-REQ artifacts; rivet validate clean.

Sample emitted Mermaid

classDiagram (spar emit --format mermaid-class --root Emit_Test::TestSys.Impl):

classDiagram
    class App {
        <<process>>
    }
    class TestCpu {
        <<processor>>
    }
    class TestSys {
        <<system>>
    }
    class Worker {
        <<thread>>
    }
    App --|> TestSys
    TestCpu --|> TestSys
    Worker --|> App

requirementDiagram (spar emit --format mermaid-req, excerpt):

requirementDiagram

    requirement REQ_PARSE_001 {
        id: "REQ-PARSE-001"
        text: "AADL v2.2 lexical and syntactic parsing"
        risk: undefined
        verifymethod: analysis
    }

    requirement REQ_MERMAID_CLASS_001 {
        id: "REQ-MERMAID-CLASS-001"
        text: "classDiagram emitter for AADL component types"
        risk: undefined
        verifymethod: analysis
    }

Test plan

• cargo test -p spar-mermaid — 12 tests pass (6 original + 6 new)
• cargo test -p spar --test emit_mermaid — 4 tests pass (2 original + 2 new)
• cargo clippy --workspace -- -D warnings — clean
• cargo fmt --check — clean
• rivet validate — no errors (pre-existing WARNs only, unchanged)

Follow-on to #220 / #222 (M3 milestone).

🤖 Generated with Claude Code

[github-actions]

Rivet verification gate

✅ 19/19 passed

	count
Passed	19
Failed	0
Skipped (no steps)	0

Filter: (and (= type "feature") (or (has-tag "v093") (has-tag "v0100")))

Failed artifacts

(none)

_{Updated automatically by tools/post_verification_comment.py. Source of truth: artifacts/verification.yaml.}

[codecov]

Codecov Report

❌ Patch coverage is 86.88525% with 48 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/spar-mermaid/src/lib.rs	87.75%	42 Missing ⚠️
crates/spar-cli/src/main.rs	73.91%	6 Missing ⚠️

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