feat(tickets): ajoute les pièces jointes sur tickets (#108)

Stockage flat côté ticket + métadonnées d'attachments, lecture exposée côté
backend/MCP, et UI minimale de liste/ajout dans TicketDetail. Traverse le
domaine (Issue, ports), l'application (usecases + assistant de ticket), les
adaptateurs infra/MCP (issues store, orchestrateur), les DTO backend/web-
server/app-tauri, et le frontend (domain/ports/adapters/hooks/UI).

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

crates/backend/src/ticket_dto.rs

@@ -10,9 +10,10 @@ use application::{
     BulkUpdateIssueStatusInput, CreateIssueInput, UpdateIssueInput,
 };
 use domain::{
-    AgentId, AgentIssueRole, Issue, IssueActor, IssueCarnet, IssueIndexEntry, IssueLink,
-    IssueLinkKind, IssueListFilter, IssuePriority, IssueRef, IssueStatus, IssueVersion, ProfileId,
-    Project, SprintId, SprintStatus, SprintVersion,
+    AgentId, AgentIssueRole, Issue, IssueActor, IssueAttachment, IssueAttachmentContent,
+    IssueAttachmentId, IssueCarnet, IssueIndexEntry, IssueLink, IssueLinkKind, IssueListFilter,
+    IssuePriority, IssueRef, IssueStatus, IssueVersion, ProfileId, Project, SprintId, SprintStatus,
+    SprintVersion,
 };
 use infrastructure::TicketToolError;
 
@@ -36,6 +37,7 @@ pub struct TicketDto {
     pub carnet: Option<String>,
     pub links: Vec<TicketLinkDto>,
     pub assigned_agent_ids: Vec<String>,
+    pub attachments: Vec<TicketAttachmentDto>,
     pub created_by: TicketActorDto,
     pub updated_by: TicketActorDto,
     pub created_at: u64,
@@ -69,6 +71,31 @@ pub struct TicketListDto {
     pub next_cursor: Option<String>,
 }
 
+/// Public attachment metadata DTO.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TicketAttachmentDto {
+    pub id: String,
+    pub filename: String,
+    pub mime: String,
+    pub size_bytes: u64,
+    pub added_by: TicketActorDto,
+    pub added_at: u64,
+    pub summarized_in_carnet: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub summarized_by: Option<TicketActorDto>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub summarized_at: Option<u64>,
+}
+
+/// Raw attachment content DTO.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TicketAttachmentContentDto {
+    pub attachment: TicketAttachmentDto,
+    pub content_base64: String,
+}
+
 /// Sprint context embedded in ticket read/list responses.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -186,6 +213,39 @@ pub struct TicketDeleteRequestDto {
     pub r#ref: String,
 }
 
+/// Add attachment request.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TicketAttachmentAddRequestDto {
+    #[serde(default)]
+    pub project_id: String,
+    pub r#ref: String,
+    pub path: String,
+    pub mime: Option<String>,
+    pub expected_version: u64,
+}
+
+/// Read attachment request.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TicketAttachmentReadRequestDto {
+    #[serde(default)]
+    pub project_id: String,
+    pub r#ref: String,
+    pub attachment_id: String,
+}
+
+/// Mark attachment summarized request.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TicketAttachmentMarkSummarizedRequestDto {
+    #[serde(default)]
+    pub project_id: String,
+    pub r#ref: String,
+    pub attachment_id: String,
+    pub expected_version: u64,
+}
+
 /// List request.
 #[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -437,6 +497,11 @@ impl TicketDto {
                 .filter(|r| r.role == AgentIssueRole::Assigned)
                 .map(|r| r.agent_id.to_string())
                 .collect(),
+            attachments: issue
+                .attachments
+                .into_iter()
+                .map(TicketAttachmentDto::from)
+                .collect(),
             created_by: TicketActorDto::from(issue.created_by),
             updated_by: TicketActorDto::from(issue.updated_by),
             created_at: issue.created_at,
@@ -547,6 +612,31 @@ impl From<IssueActor> for TicketActorDto {
     }
 }
 
+impl From<IssueAttachment> for TicketAttachmentDto {
+    fn from(attachment: IssueAttachment) -> Self {
+        Self {
+            id: attachment.id.as_str().to_owned(),
+            filename: attachment.filename,
+            mime: attachment.mime,
+            size_bytes: attachment.size_bytes,
+            added_by: TicketActorDto::from(attachment.added_by),
+            added_at: attachment.added_at,
+            summarized_in_carnet: attachment.summarized_in_carnet,
+            summarized_by: attachment.summarized_by.map(TicketActorDto::from),
+            summarized_at: attachment.summarized_at,
+        }
+    }
+}
+
+impl From<IssueAttachmentContent> for TicketAttachmentContentDto {
+    fn from(content: IssueAttachmentContent) -> Self {
+        Self {
+            attachment: TicketAttachmentDto::from(content.attachment),
+            content_base64: URL_SAFE_NO_PAD.encode(content.bytes),
+        }
+    }
+}
+
 impl TryFrom<TicketCreatorFilterDto> for IssueActor {
     type Error = ErrorDto;
 
@@ -560,6 +650,13 @@ impl TryFrom<TicketCreatorFilterDto> for IssueActor {
     }
 }
 
+pub fn parse_attachment_id_dto(raw: &str) -> Result<IssueAttachmentId, ErrorDto> {
+    IssueAttachmentId::new(raw.to_owned()).map_err(|err| ErrorDto {
+        code: "INVALID".to_owned(),
+        message: err.to_string(),
+    })
+}
+
 impl From<IssueCarnet> for TicketCarnetDto {
     fn from(carnet: IssueCarnet) -> Self {
         Self {