feat(agent): fondation exécution structurée des agents IA (D0+D1) — §17

Pivot orchestration : agents IA pilotés via leur mode programmatique/JSON
(capture déterministe), au lieu du TUI brut + self-report. §16 (idea/MCP)
marquée remplacée comme voie principale.

- D0 (domaine) : port AgentSession + AgentSessionFactory, types ReplyEvent
  /ReplyStream/AgentSessionError, champ AgentProfile.structured_adapter
  (Option<StructuredAdapter{Claude,Codex}>, skip si None ⇒ zéro régression),
  catalogue Claude/Codex annotés.
- D1 (application) : registre StructuredSessions (jumeau de TerminalSessions),
  agrégateur LiveSessions{pty,structured} derrière LiveAgentRegistry (vivant si
  PTY OU structuré, surface du trait inchangée), helper send_blocking (draine le
  ReplyStream jusqu'au Final, Timeout sans tuer la session).

Tests : domaine 16+2 ; application registre 11 + send_blocking 9 ; workspace 0 échec.
A/B intacts. Aucun adapter concret (D2), pas de Tauri/front.

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

Cargo.toml

@@ -18,7 +18,7 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 thiserror = "2"
 async-trait = "0.1"
-tokio = { version = "1", features = ["rt-multi-thread", "macros", "sync", "fs", "io-util"] }
+tokio = { version = "1", features = ["rt-multi-thread", "macros", "sync", "fs", "io-util", "time"] }
 # Local git via libgit2. Network features (https/ssh → openssl) are off for L8:
 # only local operations (status/commit/branch/checkout/log) are in scope; remote
 # push/pull and static vendoring for the AppImage are deferred to L9/L11.