extract api-types crate, adopt thiserror for all errors

api-types: standalone crate with DTOs (widget, data source, layout, preset)
extracted from http-api. Shared between http-api and future SPA.

thiserror: replaced all manual Display impls with derive macros across
8 crates (config-sqlite, config-memory, tcp-server, tcp-client,
http-json, rss, media, application).

Cargo.lock

@@ -8,11 +8,20 @@ version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
 
+[[package]]
+name = "api-types"
+version = "0.1.0"
+dependencies = [
+ "domain",
+ "serde",
+]
+
 [[package]]
 name = "application"
 version = "0.1.0"
 dependencies = [
  "domain",
+ "thiserror",
  "tokio",
 ]
 
@@ -228,6 +237,7 @@ name = "config-memory"
 version = "0.1.0"
 dependencies = [
  "domain",
+ "thiserror",
 ]
 
 [[package]]
@@ -238,6 +248,7 @@ dependencies = [
  "serde",
  "serde_json",
  "sqlx",
+ "thiserror",
  "tokio",
 ]
 
@@ -701,6 +712,7 @@ dependencies = [
 name = "http-api"
 version = "0.1.0"
 dependencies = [
+ "api-types",
  "application",
  "axum",
  "config-memory",
@@ -744,6 +756,7 @@ dependencies = [
  "domain",
  "reqwest",
  "serde_json",
+ "thiserror",
  "tokio",
 ]
 
@@ -1068,6 +1081,7 @@ dependencies = [
  "domain",
  "reqwest",
  "serde_json",
+ "thiserror",
  "tokio",
 ]
 
@@ -1493,6 +1507,7 @@ dependencies = [
  "quick-xml",
  "reqwest",
  "serde",
+ "thiserror",
  "tokio",
 ]
 
@@ -2012,6 +2027,7 @@ version = "0.1.0"
 dependencies = [
  "client-domain",
  "protocol",
+ "thiserror",
 ]
 
 [[package]]
@@ -2021,6 +2037,7 @@ dependencies = [
  "domain",
  "postcard",
  "protocol",
+ "thiserror",
  "tokio",
 ]