feat: add a read-only diagram viewer prototype

[transitrix-foundry]

Adds a read-only diagram viewer prototype with a local stdio MCP Apps adapter. It reuses Studio's Goals parser, validator and SVG renderer and the bundled PlantUML engine for a bounded sequence subset. The viewer provides pan/zoom/fit, Goals expansion, explicit refresh, source hashes and diagnostics; file access requires startup bindings, and write operations are rejected.

Build/use instructions and two minimal examples accompany the source. The resource is self-contained and declares no external network domains. The adapter is single-user and stdio-only; installed desktop compatibility and HTTP transport are not claimed.

Validation:

• Viewer build, protocol/source authorization checks, executable stdio smoke
• Browser rendering, navigation, expansion, refresh and error-state checks
• Repository tests: 824 core and 1,799 diagrams passed; 21 existing skips
• Root and extension compilation; diff hygiene

[github-actions]

📊 Metrics Regression Report

✅ All metrics within tolerance

Summary

• Diagrams tested: 9
• Successful: 9
• Failed: 0
• Violations: 0

Details

ai-expense-approval.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	1	1	0.00	✓
bends	6	6	0.00	✓
edgeLength	1868	1868	0.00 (0.0%)	✓
waypointDensity	2.6	2.6	0.00 (0.0%)	✓
spineDeviation	0	0	0.00	✓
emptyArea	0.48125	0.48125	0.00	✓
portViolations	0	0	0.00	✓

feature-release.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	1	1	0.00	✓
bends	13	13	0.00	✓
edgeLength	3428	3428	0.00 (0.0%)	✓
waypointDensity	3	3	0.00 (0.0%)	✓
spineDeviation	0	0	0.00	✓
emptyArea	0.5500909090909091	0.5500909090909091	0.00	✓
portViolations	0	0	0.00	✓

large-cyclic-workflow.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	2	2	0.00	✓
bends	28	28	0.00	✓
edgeLength	7479	7479	0.00 (0.0%)	✓
waypointDensity	3.12	3.12	0.00 (0.0%)	✓
spineDeviation	66	66	0.00	✓
emptyArea	0.793134974640294	0.793134974640294	0.00	✓
portViolations	1	1	0.00	✓

order-fulfillment.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	0	0	0.00	✓
bends	2	2	0.00	✓
edgeLength	728	728	0.00 (0.0%)	✓
waypointDensity	2.3333333333333335	2.3333333333333335	0.00 (0.0%)	✓
spineDeviation	0	0	0.00	✓
emptyArea	0.5622894736842106	0.5622894736842106	0.00	✓
portViolations	0	0	0.00	✓

parallel-tracks.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	0	0	0.00	✓
bends	6	6	0.00	✓
edgeLength	2104	2104	0.00 (0.0%)	✓
waypointDensity	2.6666666666666665	2.6666666666666665	0.00 (0.0%)	✓
spineDeviation	33	33	0.00	✓
emptyArea	0.6834468042259194	0.6834468042259194	0.00	✓
portViolations	0	0	0.00	✓

simple-approval.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	0	0	0.00	✓
bends	8	8	0.00	✓
edgeLength	1450	1450	0.00 (0.0%)	✓
waypointDensity	3.142857142857143	3.142857142857143	0.00 (0.0%)	✓
spineDeviation	33	33	0.00	✓
emptyArea	0.7764882411250177	0.7764882411250177	0.00	✓
portViolations	0	0	0.00	✓

simple-linear.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	0	0	0.00	✓
bends	0	0	0.00	✓
edgeLength	440	440	0.00 (0.0%)	✓
waypointDensity	2	2	0.00 (0.0%)	✓
spineDeviation	0	0	0.00	✓
emptyArea	0.5258771929824562	0.5258771929824562	0.00	✓
portViolations	0	0	0.00	✓

small-dense-approval.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	0	0	0.00	✓
bends	14	14	0.00	✓
edgeLength	2066	2066	0.00 (0.0%)	✓
waypointDensity	3.272727272727273	3.272727272727273	0.00 (0.0%)	✓
spineDeviation	33	33	0.00	✓
emptyArea	0.8091206777597997	0.8091206777597997	0.00	✓
portViolations	0	0	0.00	✓

xlarge-stress-test.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	0	1	+1.00	✓
bends	62	64	+2.00	✓
edgeLength	11526	11674	+148.00 (1.3%)	✓
waypointDensity	3.1481481481481484	3.185185185185185	+0.04 (1.2%)	✓
spineDeviation	132	132	0.00	✓
emptyArea	0.8201716840253008	0.8201716840253008	0.00	✓
portViolations	0	0	0.00	✓