Merge: a log that survives the process, so the tablet can be debugged

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

# Conflicts:
#	apps/darkroom-android/Cargo.toml
#	apps/darkroom-desktop/Cargo.toml
#	platform/dr-plat/src/lib.rs

platform/dr-plat/src/crash.rs

@@ -56,7 +56,7 @@
 //! for Android where XDG does not exist), [`redact`] (NFR-OPS-1's "automatic
 //! redaction of credentials and tokens" is the same function), and `prune`
 //! (size-capped rotation is this counting files instead of bytes). A log
-//! belongs at `state_dir().join("log")` beside `crash/`, and the diagnostics
+//! belongs beside `crash/` on desktop, and the diagnostics
 //! bundle then has one directory to collect.
 
 use std::path::{Path, PathBuf};