feat(wave): #119/#122/#131/#132 verts + sprint plugins ESM/persistance #135/#136/#139

État d'intégration confiné à la branche batch. Les tickets #119 (skills →
capacités agent découvrables), #122 (override permissions par défaut), #131
(effort par agent/presets) et #132 (outil MCP d'édition du contexte projet)
sont verts en périmètre. Le sprint plugins multi-fichiers ESM / persistance
plugin-owned (#135/#136/#139) est co-implémenté dans les MÊMES fichiers de
câblage (frontend/src/ports/index.ts, backend/src/lib.rs, domain/ports.rs,
backend/dto.rs), inséparable sans staging interactif (indisponible ici).

Commit unique volontaire : préserve l'état vert QA sans découpe hunk risquée.
NON mergé vers develop tant que #137 (QA e2e plugins) n'est pas vert.

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

crates/domain/src/orchestrator.rs

@@ -194,6 +194,9 @@ pub struct OrchestratorRequest {
     /// `memory.write`, cadrage C7). Required by those actions, ignored otherwise.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub content: Option<String>,
+    /// Optional optimistic-concurrency version for `context.update`.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub if_match: Option<String>,
     /// Target memory note slug for the memory tools (`memory.read`/`memory.write`,
     /// cadrage C7). Required by `memory.write`; optional for `memory.read` (absent ⇒
     /// the aggregated index). Ignored by the other actions.
@@ -342,6 +345,16 @@ pub enum OrchestratorCommand {
         /// The proposing party (handshake identity).
         requester: ConversationParty,
     },
+    /// Directly update the global project context. Strict, orchestrator-only
+    /// counterpart to [`Self::ProposeContext`].
+    UpdateProjectContext {
+        /// The new Markdown body.
+        content: String,
+        /// Optional expected current version.
+        if_match: Option<String>,
+        /// The writing party (handshake identity).
+        requester: ConversationParty,
+    },
     /// Read a memory note under the [`crate::fileguard::FileGuard`] (cadrage C7).
     /// `slug` absent = the aggregated `MEMORY.md` index; otherwise one note.
     ReadMemory {
@@ -500,6 +513,11 @@ impl OrchestratorRequest {
                 content: self.require("content", action, self.content.as_deref())?,
                 requester: self.requester_party(),
             }),
+            "context.update" => Ok(OrchestratorCommand::UpdateProjectContext {
+                content: self.require("content", action, self.content.as_deref())?,
+                if_match: self.if_match.clone(),
+                requester: self.requester_party(),
+            }),
             "memory.read" => Ok(OrchestratorCommand::ReadMemory {
                 slug: self.optional_slug(),
                 requester: self.requester_party(),
@@ -1089,6 +1107,34 @@ mod tests {
         );
     }
 
+    #[test]
+    fn context_update_command_parses_content_and_if_match() {
+        let uid = uuid::Uuid::from_u128(42);
+        let r = req(&format!(
+            r##"{{ "type":"context.update", "requestedBy":"{uid}", "content":"# body", "ifMatch":"abc123" }}"##
+        ));
+        assert_eq!(
+            r.validate().unwrap(),
+            OrchestratorCommand::UpdateProjectContext {
+                content: "# body".to_owned(),
+                if_match: Some("abc123".to_owned()),
+                requester: ConversationParty::agent(AgentId::from_uuid(uid)),
+            }
+        );
+    }
+
+    #[test]
+    fn context_update_requires_content() {
+        let missing = req(r#"{ "type":"context.update", "ifMatch":"abc123" }"#);
+        assert_eq!(
+            missing.validate(),
+            Err(OrchestratorError::MissingField {
+                action: "context.update".to_owned(),
+                field: "content".to_owned(),
+            })
+        );
+    }
+
     #[test]
     fn memory_read_optional_slug() {
         assert_eq!(