fix(build): remove dead sync-extension-compiler script and stale log

[transitrix]

Summary

• Removes scripts/sync-extension-compiler.mjs — a hand-copy script that synced compiled dist/*.js and schemas to extension/compiler/ and extension/schemas/. It has been dead code since build-compiler-bundle.mjs was introduced: that script bundles the same entries via esbuild, syncs the same schemas, and installs runtime deps. Zero external references remained in package.json, CI, or docs.
• Removes the stale backends → extension/backends/ fragment from the build-compiler-bundle.mjs success log. The Python/svgbob backend was removed in a prior pass; the script now cleans that directory rather than populating it, so the log entry was misleading.

No behaviour change. 839 tests pass.

Test plan

• npm test — 839 passed (56 test files)
• npm run compile — type-check clean
• Confirmed zero references to sync-extension-compiler in package.json, .github/, docs/, scripts/

🤖 Generated with Claude Code

[github-actions]

📊 Metrics Regression Report

✅ All metrics within tolerance

Summary

• Diagrams tested: 8
• Successful: 8
• Failed: 0
• Violations: 0

Details

ai-expense-approval.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	1	1	0.00	✓
bends	10	10	0.00	✓
edgeLength	1992.6666666666665	1992.6666666666665	0.00 (0.0%)	✓
waypointDensity	3	3	0.00 (0.0%)	✓
spineDeviation	0	0	0.00	✓
emptyArea	0.5869700748129676	0.5869700748129676	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	3460	3460	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	1	1	0.00	✓
bends	29	29	0.00	✓
edgeLength	7042.666666666667	7042.666666666667	0.00 (0.0%)	✓
waypointDensity	3.16	3.16	0.00 (0.0%)	✓
spineDeviation	82	82	0.00	✓
emptyArea	0.7965322633390317	0.7965322633390317	0.00	✓
portViolations	2	2	0.00	✓

order-fulfillment.bpmn.transitrix.yaml

Metric	Baseline	Current	Delta	Status
crossings	0	0	0.00	✓
bends	2	2	0.00	✓
edgeLength	704	704	0.00 (0.0%)	✓
waypointDensity	2.3333333333333335	2.3333333333333335	0.00 (0.0%)	✓
spineDeviation	0	0	0.00	✓
emptyArea	0.5462701149425288	0.5462701149425288	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	1542	1542	0.00 (0.0%)	✓
waypointDensity	3.142857142857143	3.142857142857143	0.00 (0.0%)	✓
spineDeviation	41	41	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	2158	2158	0.00 (0.0%)	✓
waypointDensity	3.272727272727273	3.272727272727273	0.00 (0.0%)	✓
spineDeviation	41	41	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	1	1	0.00	✓
bends	90	90	0.00	✓
edgeLength	11756.583333333332	11756.583333333332	0.00 (0.0%)	✓
waypointDensity	3.6666666666666665	3.6666666666666665	0.00 (0.0%)	✓
spineDeviation	148	148	0.00	✓
emptyArea	0.8282701728700941	0.8282701728700941	0.00	✓
portViolations	0	0	0.00	✓