orpc-v2: Stage A integrate and verify (wire-compatible Effect 4)

[elliotBraem]

Ticket ID: A5

Parent

#248 — orpc-v2: consolidate fork into everything-dev and migrate platform to oRPC v2 + Effect 4 (epic)

What to build

Stage A gate: integrate the Effect 4 work on the effect-4 branch and verify the whole platform wire-compatibly. Full monorepo test/lint/typecheck, browser + api regression suites against a spawned stack, dev-stack smoke. Merge Stage A to main — Stage B (orpc-v2 branch) cuts from here.

Acceptance criteria

• effect-4 branch: full test + lint + typecheck + regression suites (browser + api) green
• Dev stack smoke passes; deployed wire contract unchanged
• Stage A merged to main; go decision for Stage B recorded on the epic
• orpc-v2 integration branch cut from merged main

Blocked by

• orpc-v2: host and api on Effect 4 #255 — host and api on Effect 4
• orpc-v2: all five plugins on Effect 4 #256 — all five plugins on Effect 4