feat(inter-agent): backend des annonces live d'agent (B0-B3)

Redémarre le ticket #4 sur la base develop. Émission d'annonces live d'un
agent vers l'UI, distinctes du Final de délégation :

- domain: ReplyEvent::Announcement/Final et DomainEvent::AgentAnnouncement
  (events.rs), port d'émission (ports.rs), gating de readiness (readiness.rs).
- application: mapping des événements structurés en annonces
  (agent/structured.rs, agent/mod.rs, lib.rs) et relais côté orchestrateur
  (orchestrator/service.rs).
- infrastructure/session: parse des annonces + fix du Final pour Claude et
  Codex, propagé aux adaptateurs et à la conformance
  (claude.rs, codex.rs, conformance.rs, mod.rs, process.rs, sandbox_e2e.rs).
- app-tauri: relais Tauri des annonces vers le front (events.rs, chat.rs).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/application/src/lib.rs

@@ -33,9 +33,10 @@ pub mod window;
 pub mod workstate;
 
 pub use agent::{
-    drain_reply_stream_with_readiness, drain_with_readiness, drain_with_readiness_outcome,
-    reference_profile_id, reference_profiles, selectable_reference_profiles, send_blocking,
-    AgentResumer, ChangeAgentProfile, ChangeAgentProfileInput, ChangeAgentProfileOutput,
+    drain_reply_stream_with_readiness, drain_with_readiness,
+    drain_with_readiness_and_announcements, drain_with_readiness_outcome, reference_profile_id,
+    reference_profiles, selectable_reference_profiles, send_blocking, AgentResumer,
+    AnnouncementPublisher, ChangeAgentProfile, ChangeAgentProfileInput, ChangeAgentProfileOutput,
     ConfigureProfiles, ConfigureProfilesInput, ConfigureProfilesOutput, CreateAgentFromScratch,
     CreateAgentInput, CreateAgentOutput, DeleteAgent, DeleteAgentInput, DeleteProfile,
     DeleteProfileInput, DetectProfiles, DetectProfilesInput, DetectProfilesOutput, FirstRunState,