Preserve both endpoints when repairing devtools chart routes

[SandroMaglione]

Summary

Fix valid devtools charts failing with wrong-source-direction when a retry edge targets a compound state. CopyButton's Failed → Working edge initially leaves its source correctly, but moving the destination to the Working header previously rewrote the source segment too.

Both endpoint repairs now share one implementation. It preserves an attached opposite endpoint, reserves clearance on straight routes before adding a detour, and checks both endpoint directions after route compaction. The existing chart geometry validator remains strict.

Before: repair source → repair destination can overwrite the source exit
After:  repair either endpoint while preserving the opposite attachment and exit

Add six CopyButton topology variants and eight rotated/reversed geometry cases. Five of these tests fail against the base implementation; all fourteen pass with the fix. The existing 30 chart tests also pass. Layout failures now identify chart routing rather than attributing postprocessing defects to ELK.

Full validation also exposed a fresh-install CLI failure: platform-node's dependency range selected platform-node-shared RC.115 alongside Effect RC.112. Pin platform-node-shared to the already-supported RC.112 and require the platform packages to stay aligned with the Effect peer version. This adds no version upgrade and restores the existing packed-consumer test without changing its checks.

Changeset

• Added or updated for a library or package-metadata change
• Not required because this PR does not change a publishable package

Patch changeset for the chart fix and compatible fresh-install dependency correction. Package versions continue to release together through the fixed group.

Validation

• pnpm check

• Automated type-performance measurement passed or was not required

• Automated runtime- and memory-performance measurement passed or was not required

• pnpm perf:runtime completed as a local functional smoke test; no performance comparison is claimed from this run.

• Built and visually inspected CopyButton in the actual browser devtools. The chart renders with an outward retry edge and an attached destination at the Working header.

• Fresh packed-consumer CLI, worker, browser, static build, live reload, shutdown, and failure-handling checks passed after pinning the shared platform dependency.

• No public machine API, inference, planner, runtime execution, or memory-ownership changes. Both CI performance gates passed with MEASUREMENT_REQUIRED=false and MEASUREMENT_RESULT=skipped; no base-versus-PR measurement report is required for this scope.