refactor: remove legacy API compatibility paths #3108

Job	Run time
Detect changed paths	8s
Dependency review	9s
RSC runtime micro-eval (Node 22.19)	38s
Host install proofs (Node 22.19)	3m 43s
Examples check (Node 22.19)	5m 25s
Host filesystem (windows-latest)	2m 54s
Release gates (Node 22.19)	4m 39s
Host filesystem (macos-latest)	2m 42s
Host filesystem (ubuntu-latest)	1m 14s
Verify (fast, Node 24)	4m 43s
Verify (integration-2, Node 24)	8m 33s
Verify (integration-1, Node 24)	5m 24s
Verify (fast, Node 26)	4m 40s
Verify gate	4s
Candidate status	0s
	44m 56s

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