feat(core): app composition and full request handler pipeline

[viniciusdacal]

Summary

• Implements createApp() builder with .register(), .middlewares(), and .handler getter
• App runner builds a Trie from registered module routers, runs middleware chain, builds ctx via buildCtx(), handles CORS, error responses
• Service injection: router inject field resolved at boot time, services available in handler ctx
• Module options propagated to handler via ctx.options
• Immutable ctx in development mode via makeImmutable()

Test plan

• createApp() returns builder with register, middlewares, handler
• Routes GET request to correct handler, returns JSON
• Returns 404 for unmatched route
• Passes parsed params to handler via ctx
• Parses request body for POST routes
• Handles VertzException with correct status code
• Handles unexpected errors with 500
• Returns 405 with Allow header for wrong method
• Registers multiple modules and combines routes
• CORS preflight returns 204
• Middleware chain runs, contributions available in handler ctx
• Returns 204 when handler returns undefined
• Middleware exception short-circuits chain
• basePath prepended to all routes
• CORS headers applied to actual responses
• Injects services into handler ctx via router inject
• Module options accessible via ctx.options
• Immutable ctx in development mode
• 154 tests pass across full suite

🤖 Generated with Claude Code

[viniciusdacal]

Post-PR Review

Overall: Solid integration phase. Wires together all prior phases (trie, middleware, context, CORS, error handling) into a clean request pipeline.

Architecture

• app-builder.ts — Clean builder pattern with lazy handler construction via getter
• app-runner.ts — Well-decomposed with resolveServices, resolveMiddlewares, resolveRouterServices, registerRoutes helper functions
• Uses buildCtx() for immutability and collision detection (addresses pre-PR finding)
• Service injection resolved at boot time, not per-request

Reviewed

• Request pipeline: CORS → parse → trie match → body parse → middleware → buildCtx → handler → response
• Error handling: VertzException → serialized status, unexpected → 500
• 404/405 distinction with Allow header
• 204 for void handlers
• basePath prepended to all routes
• Module options threaded through to ctx.options
• Router inject resolved from instantiated service map

No actionable findings

• The entry as any cast in trie storage is pragmatic — the Trie accepts RouteHandler but we store RouteEntry. This works because the trie never calls the handler directly; the app runner casts it back.
• env: {} is hardcoded — acceptable for now since env is created eagerly at import time and will be passed through in Phase 12 (public API wiring)

LGTM ✅