feat(dev): isolate requests in parent-owned workers

[ctgowrie]

Why

Nitro currently owns both the public dev listener and its reloadable runtime. Replacing that runtime can reset admitted HTTP or WebSocket traffic, lose the original client address, and make shutdown wait on streams whose producer has not stopped.

What changed

• Keep one parent-owned listener while ready-gated worker candidates move through candidate, active, retired, and closed states.
• Bind each admission to one worker and the latest published artifact generation; release leases idempotently on finish, error, disconnect, cancellation, and shutdown.
• Propagate cancellation in both directions and stop workers, active streams, and sockets before awaiting listener closure.
• Move runtime-artifact control requests into the parent so candidate replacement cannot reset them.
• Pass client addresses through signed parent-to-worker metadata, strip that metadata before authored HTTP and WebSocket handlers, and reject spoofed values.
• Vendor the internal worker transport implementation so eve gains no runtime dependency.

Validation

• Unit: 448 files; 4,689 passed, 1 skipped.
• Integration: 62 files; 440 passed.
• Scenario: 53 files; 311 passed, 15 skipped.
• Focused packaged dev scenarios cover ready replacement, retained WebSockets, runtime-generation HMR, startup-generation pruning, streamed turns, and absence of ECONNRESET/socket-hang-up logs.
• Formatting, lint, workspace typecheck, and invariant guard pass.

Stack

Depends on #759 (immutable generation artifacts). Stage 4 will make watcher, pointer, route, and worker promotion one transaction. Stage 5 will move the local Workflow World and queue ownership into the parent and add durable generation references plus pruning.

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Project	Deployment	Actions	Updated (UTC)
eve-docs	Building	Preview, Comment	Jul 14, 2026 12:26pm

2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
eve-docs-1644	Skipped		Jul 14, 2026 12:26pm
eve-docs-4759	Skipped		Jul 14, 2026 12:26pm