Plan M5a: local memory in 15 tasks

memoryd (files, the check, edits, journal, index, recall, serving),
the memory tools and built-in grants in brokerd, the memory block in
loopd, bxctl reindex and memory, and the device checks with memoryd.

Each task was built as a reference and gated. Each was replayed on its
own at its end state (854 to 936 tests) and mutation-checked. Each
skeleton compiles and fails its tests. Every todo comment was read
beside its signature.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/plans/M5a/files/crates/loopd/tests/support/memoryd.rs

@@ -0,0 +1,40 @@
+//! Starting `memoryd` for the device tests, with the repository's starter `soul.md`: `loopd`
+//! starts no session without the memory block. Do not edit.
+
+use std::path::Path;
+use std::process::{Child, Command};
+use std::thread;
+use std::time::Duration;
+
+/// Write `memoryd.toml` into `home`, start `memoryd serve`, and wait for its `loopd` socket.
+pub fn start(home: &Path) -> Child {
+    let root = Path::new(env!("CARGO_MANIFEST_DIR")).join("../..");
+    let config = home.join("memoryd.toml");
+    std::fs::write(
+        &config,
+        format!(
+            "[paths]\nhome = \"{}\"\n[memory]\nsoul_starter = \"{}\"\n",
+            home.display(),
+            root.join("config/soul.md").display()
+        ),
+    )
+    .unwrap();
+    let socket = home.join("run").join("loop-memory").join("memory.sock");
+    let _ = std::fs::remove_file(&socket);
+    let bin = std::env::var("BOXMAKER_MEMORYD").expect("BOXMAKER_MEMORYD is not set");
+    let mut child = Command::new(bin)
+        .arg("serve")
+        .arg("--config")
+        .arg(&config)
+        .spawn()
+        .expect("cannot start memoryd");
+    for _ in 0..600 {
+        if socket.exists() {
+            return child;
+        }
+        thread::sleep(Duration::from_millis(100));
+    }
+    let _ = child.kill();
+    let _ = child.wait();
+    panic!("memoryd did not come up within 60 s");
+}