orpc-v2: createPlugin restructure (Layer-based initialize, errorStatusMap, scope lifecycle)

[elliotBraem]

Ticket ID: B2

Parent

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

What to build

Stage B, step 2: restructure every-plugin's createPlugin for v2 + Effect 4:

• initialize composes Effect Layers; scoped resources (db pools, repositories, caches, publishers) bind to the plugin lifecycle scope via Layer semantics — replacing the tools/buildService pattern.
• Per-plugin context bridging moves to effect/context composed by a base-builder middleware — the per-plugin context-bridge modules go away.
• errorStatusMap plumbing lands here with custom entries TIMEOUT: 504 and CONNECTION_ERROR: 502 (v2's default TIMEOUT: 408 would change current HTTP behavior).
• v2 removes middleware dedup — audit middleware call sites and add context-flag guards where double-apply was relied on.

Acceptance criteria

• createPlugin's new contract implemented with Layer-based initialize; tools/buildService removed
• Scope-lifecycle tests prove resources release on plugin shutdown
• errorStatusMap carries TIMEOUT: 504, CONNECTION_ERROR: 502
• Middleware double-apply sites guarded; every-plugin suite green

Blocked by

• orpc-v2: deps bump + every-plugin v2 surface (barrels, route extension, publisher rename) #258 — deps bump + every-plugin v2 surface