fix(core): support symbol and prototype-named events

[buiducnhat]

Summary

Fixes #50 — symbol and prototype-named events fail during registration or dispatch.

Problem

The event API accepts symbol names in ctx.on(), but dispatching the same symbol throws before its listener can run. A string matching an inherited Object.prototype property (e.g. __proto__) also fails during registration.

const ctx = new Context()
const symbol = Symbol('example')
ctx.on(symbol, () => {})
ctx.emit(symbol)
// TypeError: name.startsWith is not a function

ctx.on('__proto__', () => {})
// TypeError: hooks[method] is not a function

Root cause

• EventsService._hooks was initialized as a plain object, so _hooks['__proto__'] resolved to the inherited prototype instead of a listener array.
• EventsService._resolve() narrowed every event name to string and called startsWith() unconditionally, which fails for symbols.

Fix

• Initialize _hooks with Object.create(null) so string names never collide with Object.prototype members.
• Guard the internal-prefix check in _resolve() so it only runs on string names (typeof name === 'string' && name.startsWith('internal/')).
• Widen the internal/dispatch event name type to string | symbol.

Tests

Added three test cases in packages/core/tests/events.spec.ts:

• symbol events register and dispatch via emit (and dispose cleanly)
• symbol events dispatch across emit/parallel/serial/bail
• __proto__ registers, dispatches, and releases its bucket on dispose

All 74 core tests pass. The core package builds and type-checks cleanly.