docs: fold completed FIXDRY audit into a decision log

devenv.lock

@@ -67,11 +67,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1779592685,
-        "narHash": "sha256-p9d56GezhHRf4QfANxwa1d+fvwShvjB5XUhdIl7WEd0=",
+        "lastModified": 1783144302,
+        "narHash": "sha256-NQnzmXwpEAd5tjMBh2+P/y9NknF+WHv5+6yoXoN4h/Y=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "3a58b199e7c83a80b85c28044f808085ba7e941c",
+        "rev": "fe5aee0952e8e1525533d61defd9e36513db811b",
         "type": "github"
       },
       "original": {

docs/DECISIONS.md

@@ -0,0 +1,34 @@
+# Decision log
+
+Durable "why we did it this way" records that are not obvious from the code.
+Add a dated entry when a non-obvious architectural or dependency decision is
+made or revisited.
+
+## 2026-07: Infrastructure we keep custom instead of using a crate
+
+A dependency audit replaced most general-purpose infrastructure code with
+mature crates (`tempfile`, `which`, `plist`, `walkdir`, `xshell`, `sysinfo`,
+`fs-err`, `backon`, `opener`, `etcetera`, and others — see the git history of
+`FIXDRY.md` for the full list). The following stayed custom, deliberately:
+
+- `openlogi-core::single_instance`: the `single-instance` crate uses different
+  backends (for example abstract Unix sockets on Linux) and does not preserve
+  OpenLogi's data-dir lock-file path, per-role names, and error classification
+  closely enough to be a safe deletion.
+- Agent tray Quit's `openlogi://quit` dispatch keeps
+  `std::process::Command::output()` intentionally: it blocks until
+  LaunchServices accepts the Apple Event, while generic opener crates only
+  guarantee process spawn.
+- GUI helper launch keeps `/usr/bin/open -g -n` intentionally: it needs
+  LaunchServices-specific flags to start the packaged agent under its own TCC
+  identity, which generic opener crates do not expose.
+- Agent autostart install keeps direct `systemctl` calls because it is managing
+  systemd user units, not merely opening or spawning an arbitrary program.
+- Self-restart and `disclaim` launches stay custom because they are process
+  identity / update lifecycle boundaries, not generic command orchestration.
+- `openlogi-hook`: event suppression/rewriting and foreground-app lookup are
+  OpenLogi-specific and not covered cleanly by generic input crates.
+- `openlogi-inject`: platform-specific action synthesis may overlap with
+  `enigo`, but current semantics are narrower and more controlled.
+- `openlogi-hid` / vendored `openlogi-hidpp`: the right path is upstreaming
+  OpenLogi-specific fixes, not replacing the fork blindly.