[NFR]: Decouple collectors from framework event names (bridge + canonical signals)

[niden]

Summary

Collectors gather data by subscribing to MVC-specific event names, so nothing collects under ADR or any non-MVC stack. Introduce a neutral seam - a canonical debug-bar signal set, a per-framework bridge, and a direct push API - so collectors receive data regardless of the host application's event vocabulary, or the absence of one.

Current coupling

Collectors call subscribe(ManagerInterface $eventsManager) and attach to framework event names:

• DatabaseCollector → db:beforeQuery, db:afterQuery
• ViewCollector → view:beforeRenderView, view:afterRenderView
• RouteCollector → router:matchedRoute
• ExceptionsCollector → dispatch:beforeException
• CacheCollector → cache events

These names are emitted by the MVC stack. ADR fires a different vocabulary (APPLICATION_*, ADR_*, PIPELINE_*), and some hosts have no events manager at all.

Proposed direction (three layers)

1. Canonical signal set owned by the bar - a small, stable vocabulary (query, view.rendered, route.matched, request.received, response.sending). Collectors subscribe only to these.
2. Per-framework bridge that maps native signals to canonical ones. The MVC bridge listens to db:afterQuery / view:* / router:matchedRoute and re-emits canonical signals (current behavior, refactored behind the bridge). The ADR bridge listens to PIPELINE_* / APPLICATION_*, or instruments directly where no matching event exists.
3. Direct push API on collectors (e.g. record(...)) for hosts with no events manager - the bridge pushes directly.

The events manager becomes an implementation detail of the active bridge, not a hard dependency of the collectors.

Acceptance

• A collector receives data through the canonical signals with no reference to a framework-specific event name.
• The MVC bridge preserves current behavior (as used by phalcon/vokuro), verified by the existing tests.
• A collector can be fed with no events manager present (push API).