chore: rename quicproquo → quicprochat in Rust workspace

Rename all crate directories, package names, binary names, proto
package/module paths, ALPN strings, env var prefixes, config filenames,
mDNS service names, and plugin ABI symbols from quicproquo/qpq to
quicprochat/qpc.

crates/quicprochat-server/src/v2_handlers/blob.rs

@@ -0,0 +1,101 @@
+//! Blob handlers — chunked file upload/download.
+
+use std::sync::Arc;
+
+use bytes::Bytes;
+use prost::Message;
+use quicprochat_proto::qpc::v1;
+use quicprochat_rpc::method::{HandlerResult, RequestContext};
+
+use crate::domain::blobs::BlobService;
+use crate::domain::types::{CallerAuth, DownloadBlobReq, UploadBlobReq};
+
+use super::{domain_err, require_auth, ServerState};
+
+fn caller_auth(identity_key: Vec<u8>) -> CallerAuth {
+    CallerAuth {
+        identity_key,
+        token: Vec::new(),
+        device_id: None,
+    }
+}
+
+pub async fn handle_upload_blob(state: Arc<ServerState>, ctx: RequestContext) -> HandlerResult {
+    let identity_key = match require_auth(&state, &ctx) {
+        Ok(ik) => ik,
+        Err(e) => return e,
+    };
+
+    let req = match v1::UploadBlobRequest::decode(ctx.payload) {
+        Ok(r) => r,
+        Err(e) => {
+            return HandlerResult::err(
+                quicprochat_rpc::error::RpcStatus::BadRequest,
+                &format!("decode: {e}"),
+            )
+        }
+    };
+
+    let svc = BlobService {
+        data_dir: state.data_dir.clone(),
+    };
+    let auth = caller_auth(identity_key);
+
+    let domain_req = UploadBlobReq {
+        blob_hash: req.blob_hash,
+        chunk: req.chunk,
+        offset: req.offset,
+        total_size: req.total_size,
+        mime_type: req.mime_type,
+    };
+
+    match svc.upload_blob(domain_req, &auth) {
+        Ok(resp) => {
+            let proto = v1::UploadBlobResponse {
+                blob_id: resp.blob_id,
+            };
+            HandlerResult::ok(Bytes::from(proto.encode_to_vec()))
+        }
+        Err(e) => domain_err(e),
+    }
+}
+
+pub async fn handle_download_blob(state: Arc<ServerState>, ctx: RequestContext) -> HandlerResult {
+    let identity_key = match require_auth(&state, &ctx) {
+        Ok(ik) => ik,
+        Err(e) => return e,
+    };
+
+    let req = match v1::DownloadBlobRequest::decode(ctx.payload) {
+        Ok(r) => r,
+        Err(e) => {
+            return HandlerResult::err(
+                quicprochat_rpc::error::RpcStatus::BadRequest,
+                &format!("decode: {e}"),
+            )
+        }
+    };
+
+    let svc = BlobService {
+        data_dir: state.data_dir.clone(),
+    };
+    let auth = caller_auth(identity_key);
+
+    let domain_req = DownloadBlobReq {
+        blob_id: req.blob_id,
+        offset: req.offset,
+        length: req.length,
+    };
+
+    match svc.download_blob(domain_req, &auth) {
+        Ok(resp) => {
+            let proto = v1::DownloadBlobResponse {
+                chunk: resp.chunk,
+                total_size: resp.total_size,
+                mime_type: resp.mime_type,
+            };
+            HandlerResult::ok(Bytes::from(proto.encode_to_vec()))
+        }
+        Err(e) => domain_err(e),
+    }
+}