feat: complete daemon core milestone

Finish Milestone 3 with persisted config, socket IPC, registry CRUD,
periodic discovery, manual add, and app-cache refresh support.

Cargo.lock

@@ -288,6 +288,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "fastrand"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f1f227452a390804cdb637b74a86990f2a7d7ba4b7d5693aac9b4dd6defd8d6"
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.9"
@@ -743,6 +749,12 @@ version = "0.2.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "52ff2c0fe9bc6cb6b14a0592c2ff4fa9ceb83eea9db979b0487cd054946a2b8f"
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a66949e030da00e8c7d4434b251670a91556f4144941d37452769c25d58a53"
+
 [[package]]
 name = "litemap"
 version = "0.8.2"
@@ -1126,6 +1138,19 @@ version = "2.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94300abf3f1ae2e2b8ffb7b58043de3d399c73fa6f4b73826402a5c457614dbe"
 
+[[package]]
+name = "rustix"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
+dependencies = [
+ "bitflags",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "rustls"
 version = "0.23.38"
@@ -1356,6 +1381,19 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tempfile"
+version = "3.27.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32497e9a4c7b38532efcdebeef879707aa9f794296a4f0244f6f69e9bc8574bd"
+dependencies = [
+ "fastrand",
+ "getrandom 0.4.2",
+ "once_cell",
+ "rustix",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.18"
@@ -1624,11 +1662,13 @@ dependencies = [
  "axum",
  "chrono",
  "clap",
+ "libc",
  "md5",
  "reqwest",
  "roxmltree",
  "serde",
  "serde_json",
+ "tempfile",
  "thiserror",
  "tokio",
  "toml",