Log like a debug build on macOS, where a Mac user can find it

Nobody working on DarkRoom has a Mac, so every macOS build is in the hands
of someone who can send a log and cannot attach a debugger. Three changes
make that log worth sending:

- The desktop's default filter on macOS is `debug` for every `dr_*` crate,
  the desktop crate and `onnxruntime` (the runtime's own session log).
- The state directory — the log and crash records — is `~/Library/Logs`
  on macOS rather than the `~/.local/state` Finder hides; Console.app
  lists it. Config and data keep the Unix rules.
- A `diagnostic` cargo profile: release plus line tables, so a crash
  record's backtrace reads file:line. On macOS the tables are in the
  `.dSYM` beside the executable, which the bundle must keep.

apps/darkroom-desktop/src/main.rs

@@ -15,6 +15,22 @@ use std::path::PathBuf;
 
 use dr_plat::diagnostics::Installed;
 
+/// What the log keeps when `RUST_LOG` does not say.
+#[cfg(not(target_os = "macos"))]
+const DEFAULT_LOG: &str =
+    "info,wgpu_core=warn,wgpu_hal=warn,zbus=warn,tracing=warn,calloop=warn,rawler=warn";
+
+/// The same, and `debug` from this application's own crates and from ONNX
+/// Runtime, whose `debug` is how many nodes each provider took
+/// (docs/dev/macos.md). Nobody here runs a Mac: every macOS build is in
+/// the hands of someone who can send us a log and cannot attach a debugger,
+/// so the log is written as if for a debug build. `dr_` is a prefix, and
+/// `env_logger` matches directives by prefix, so it names every `dr-*`
+/// crate — present and future — without naming a dependency.
+#[cfg(target_os = "macos")]
+const DEFAULT_LOG: &str = "info,dr_=debug,darkroom_desktop=debug,onnxruntime=debug,\
+     wgpu_core=warn,wgpu_hal=warn,zbus=warn,tracing=warn,calloop=warn,rawler=warn";
+
 fn main() -> anyhow::Result<()> {
     // TRACES: FR-PLAT-WIN-3
     // Before the logger, the crash hook and everything else: this exists so a
@@ -33,10 +49,9 @@ fn main() -> anyhow::Result<()> {
     // (NFR-OPS-1). `filter()` is asked afterwards because the environment may
     // have overridden the default below, and the file must not be quieter than
     // the terminal.
-    let console = env_logger::Builder::from_env(env_logger::Env::default().default_filter_or(
-        "info,wgpu_core=warn,wgpu_hal=warn,zbus=warn,tracing=warn,calloop=warn,rawler=warn",
-    ))
-    .build();
+    let console =
+        env_logger::Builder::from_env(env_logger::Env::default().default_filter_or(DEFAULT_LOG))
+            .build();
     let level = console.filter();
     let logging = dr_plat::diagnostics::install(Box::new(console), level);