feat(orchestrator): create_skill action + wire per-project watchers (§14.3)

- domain: OrchestratorCommand::CreateSkill with optional scope field
  (defaults to Project, case-insensitive, UnknownScope on bad value)
- application: dispatch CreateSkill through the CreateSkill use case
- app-tauri: build OrchestratorService and start/stop per-project request
  watchers on open/create/close_project (ensure/stop_orchestrator_watch)
- tests: domain validation, service dispatch, infra watcher e2e,
  app-tauri wiring lifecycle (idempotent, isolated, stop)

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

crates/application/src/orchestrator/service.rs

@@ -23,6 +23,7 @@ use crate::agent::{
     ListAgentsInput, UpdateAgentContext, UpdateAgentContextInput,
 };
 use crate::error::AppError;
+use crate::skill::{CreateSkill, CreateSkillInput};
 use crate::terminal::{CloseTerminal, CloseTerminalInput, TerminalSessions};
 
 /// Default terminal geometry for an orchestrator-launched agent cell. The UI
@@ -39,6 +40,7 @@ pub struct OrchestratorService {
     list_agents: Arc<ListAgents>,
     close_terminal: Arc<CloseTerminal>,
     update_context: Arc<UpdateAgentContext>,
+    create_skill: Arc<CreateSkill>,
     profiles: Arc<dyn ProfileStore>,
     sessions: Arc<TerminalSessions>,
 }
@@ -61,6 +63,7 @@ impl OrchestratorService {
         list_agents: Arc<ListAgents>,
         close_terminal: Arc<CloseTerminal>,
         update_context: Arc<UpdateAgentContext>,
+        create_skill: Arc<CreateSkill>,
         profiles: Arc<dyn ProfileStore>,
         sessions: Arc<TerminalSessions>,
     ) -> Self {
@@ -70,6 +73,7 @@ impl OrchestratorService {
             list_agents,
             close_terminal,
             update_context,
+            create_skill,
             profiles,
             sessions,
         }
@@ -96,6 +100,11 @@ impl OrchestratorService {
             OrchestratorCommand::UpdateAgentContext { name, context } => {
                 self.update_agent_context(project, name, context).await
             }
+            OrchestratorCommand::CreateSkill {
+                name,
+                content,
+                scope,
+            } => self.create_skill(project, name, content, scope).await,
         }
     }
 
@@ -193,6 +202,32 @@ impl OrchestratorService {
         })
     }
 
+    /// `create_skill`: create a reusable skill in the requested scope — the same
+    /// path the UI's "New skill" action takes. For [`SkillScope::Project`] the
+    /// skill lands under `<root>/.ideai/skills/`; for [`SkillScope::Global`] the
+    /// project root is ignored by the store.
+    async fn create_skill(
+        &self,
+        project: &Project,
+        name: String,
+        content: String,
+        scope: domain::SkillScope,
+    ) -> Result<OrchestratorOutcome, AppError> {
+        let created = self
+            .create_skill
+            .execute(CreateSkillInput {
+                name: name.clone(),
+                content,
+                scope,
+                project_root: project.root.clone(),
+            })
+            .await?;
+
+        Ok(OrchestratorOutcome {
+            detail: format!("created skill {} ({:?})", created.skill.name, scope),
+        })
+    }
+
     /// Finds an agent id by display name (case-insensitive) in the project manifest.
     async fn find_agent_id_by_name(
         &self,