chore: several doc fixes and enhancements (#110)

* docs: update instructions for development flow
* feat: add devenv profile for nix/devenv environment setup
* chore: update .gitignore to ignore stage-tamagotchi-tauri fonts
* docs: add instructions to use devenv
* docs: fix note asides
* fix: missing bracket
* chore: ignore devenv related files
* chore: update ignore pattern
* chore: update .gitignore to include a newline at the end

---------

Co-authored-by: 藍+85CD <50108258+kwaa@users.noreply.github.com>

.gitignore

@@ -32,6 +32,7 @@ coverage/
 **/public/assets/vrm/models/*
 packages/stage-ui/public/assets/fonts/
 apps/stage-tamagotchi/public/assets/fonts/
+apps/stage-tamagotchi-tauri/public/assets/fonts/
 apps/stage-web/public/assets/fonts/
 
 *.pcm
@@ -40,3 +41,11 @@ apps/stage-web/public/assets/fonts/
 *.mp3
 
 twitter-session.json
+
+# Make it easy for devenv users to override their local environment.
+# See: https://github.com/moeru-ai/airi/pull/110#discussion_r2024378953
+.direnv
+.pre-commit-config.yaml
+.envrc
+.devenv*
+devenv.*