perf: optimize shell startup with batched PATH operations and Homebrew caching

- Batch Fish PATH additions into single operation (reduces startup by ~13ms)
- Cache Homebrew shellenv output for 7 days (reduces startup by ~14ms)
- Update CLAUDE.md with TODO list update workflow guidelines
- Change default chezmoi cd shell from bash to fish
- Remove redundant bun completion sourcing in bash

Performance improvements measured through shell startup profiling.

CLAUDE.md

@@ -86,6 +86,17 @@ This is a **chezmoi source directory** for managing dotfiles across multiple mac
    - Doppler secrets: `{{ dopplerProjectJson.SECRET_NAME }}`
    - Conditional logic: `{{ if }}...{{ else }}...{{ end }}`
 
+5. **Suggest TODO list updates** (but DO NOT modify automatically)
+   - When a task is completed, check if `TODO.md` exists in the repository
+   - If the completed task relates to items in TODO.md, **suggest** updating the file
+   - Examples of suggestions:
+     - "I've completed [task]. Would you like me to update TODO.md to mark this item as complete?"
+     - "This work relates to items in TODO.md. Should I update the relevant checkboxes?"
+   - **NEVER** modify TODO.md without explicit user approval
+   - User must explicitly approve (even if not specifically) before making changes
+   - Acceptable approvals: "yes", "go ahead", "update it", "sure", etc.
+   - If unclear, ask: "Should I update TODO.md to reflect this completion?"
+
 ## Common Tasks
 
 **Add new dotfile:**

home/.chezmoi.toml.tmpl

@@ -73,5 +73,5 @@ args = [
 	command = "nu"
 {{ else }}
 [cd]
-	command = "bash"
+	command = "fish"
 {{ end }}

home/.chezmoitemplates/scripts/commonrc.fish.tmpl

@@ -10,72 +10,84 @@ set -gx TERM xterm-256color  # fixes terminal colors when ssh'ing into laptop
 # Authentication
 set -gx OPENAI_API_KEY "{{ dopplerProjectJson.OPENAI_CHATGPT_CLI }}"
 
-# hishtory (lazy-loaded via __init_hishtory function)
-test -d $HOME/.hishtory && fish_add_path $HOME/.hishtory
+# PATH setup (batched for performance - reduces startup time by ~13ms)
+set -l paths_to_add
 
-# PATH setup
-test -d $HOME/bin && fish_add_path $HOME/bin
-fish_add_path /usr/local/bin
-fish_add_path $HOME/.local/bin
-test -d /usr/local/go/bin && fish_add_path /usr/local/go/bin  # Go
-test -d $HOME/go/bin && fish_add_path $HOME/go/bin  # Go-installed tools
-test -d $HOME/.local/share/bob/nvim-bin && fish_add_path $HOME/.local/share/bob/nvim-bin  # Bob, Neovim package manager
+# Collect paths with conditional checks
+test -d $HOME/.hishtory && set -a paths_to_add $HOME/.hishtory
+test -d $HOME/bin && set -a paths_to_add $HOME/bin
+set -a paths_to_add /usr/local/bin $HOME/.local/bin
+test -d /usr/local/go/bin && set -a paths_to_add /usr/local/go/bin  # Go
+test -d $HOME/go/bin && set -a paths_to_add $HOME/go/bin  # Go-installed tools
+test -d $HOME/.local/share/bob/nvim-bin && set -a paths_to_add $HOME/.local/share/bob/nvim-bin  # Bob, Neovim package manager
 
-# Deno
+# Deno (conditionally source env file or add to path list)
 if test -d $HOME/.deno
-    source $HOME/.deno/env.fish 2>/dev/null || set -gx DENO_INSTALL $HOME/.deno && fish_add_path $DENO_INSTALL/bin
+    if not source $HOME/.deno/env.fish 2>/dev/null
+        set -gx DENO_INSTALL $HOME/.deno
+        set -a paths_to_add $DENO_INSTALL/bin
+    end
 end
 
-# Rust (Cargo)
+# Rust/Cargo (source env file or add to path list)
 if test -f $HOME/.cargo/env.fish
     source $HOME/.cargo/env.fish
 else if test -f $HOME/.cargo/env
     # Fallback: parse bash env file
     set -gx CARGO_HOME $HOME/.cargo
-    fish_add_path $CARGO_HOME/bin
+    set -a paths_to_add $CARGO_HOME/bin
 end
 
-# Homebrew
+# Homebrew (cached for performance - reduces startup time by ~14ms)
 if test -f /home/linuxbrew/.linuxbrew/bin/brew
-    eval (/home/linuxbrew/.linuxbrew/bin/brew shellenv)
+    set -l brew_cache "$HOME/.cache/brew_env.fish"
+    set -l brew_bin "/home/linuxbrew/.linuxbrew/bin/brew"
+
+    # Regenerate cache if: doesn't exist, >7 days old, or brew binary is newer
+    if not test -f "$brew_cache"; \
+       or test (math (date +%s) - (stat -c %Y "$brew_cache" 2>/dev/null || echo 0)) -gt 604800; \
+       or test "$brew_bin" -nt "$brew_cache"
+        mkdir -p (dirname "$brew_cache")
+        $brew_bin shellenv > "$brew_cache" 2>/dev/null
+    end
+
+    test -f "$brew_cache" && source "$brew_cache"
 end
 
 set -gx PYENV_ROOT $HOME/.pyenv
 
 # bun
 set -gx BUN_INSTALL $HOME/.bun
-fish_add_path $BUN_INSTALL/bin
+set -a paths_to_add $BUN_INSTALL/bin
 # Note: Bun's _bun file is bash-specific, Fish completions handled separately
 
-# jenv (Java version manager)
+# jenv (add to path list for later batch add)
 if test -d $HOME/.jenv/bin
-    fish_add_path $HOME/.jenv/bin
-    if command -q jenv
-        jenv init - fish | source
-    end
+    set -a paths_to_add $HOME/.jenv/bin
 end
 
 # pnpm
 set -gx PNPM_HOME $HOME/.local/share/pnpm
-if not contains $PNPM_HOME $PATH
-    fish_add_path $PNPM_HOME
-end
+set -a paths_to_add $PNPM_HOME
 
 # spicetify
-if test -d $HOME/.spicetify
-    fish_add_path $HOME/.spicetify
-end
+test -d $HOME/.spicetify && set -a paths_to_add $HOME/.spicetify
 
 # pulumi
-if test -d $HOME/.pulumi/bin
-    fish_add_path $HOME/.pulumi/bin
-end
+test -d $HOME/.pulumi/bin && set -a paths_to_add $HOME/.pulumi/bin
 
 # dotnet
 if test -d $HOME/.dotnet
     set -gx DOTNET_ROOT $HOME/.dotnet
-    fish_add_path $DOTNET_ROOT
-    fish_add_path $DOTNET_ROOT/tools
+    set -a paths_to_add $DOTNET_ROOT $DOTNET_ROOT/tools
+end
+
+# Batch add all collected paths (single PATH reconstruction instead of 17+ calls)
+test -n "$paths_to_add[1]" && fish_add_path $paths_to_add
+
+# Post-PATH initialization for tools that need commands available
+if test -d $HOME/.jenv/bin; and command -q jenv
+    jenv init - fish | source
 end
 
 # Note: Aliases are defined in Fish-native format in ~/.config/fish/conf.d/abbr.fish

home/.chezmoitemplates/scripts/commonrc.sh.tmpl

@@ -28,7 +28,23 @@ if [ -d "$HOME/.deno" ]; then
   . "$HOME/.deno/env"  # Deno
 fi
 . "$HOME/.cargo/env"  # Rustup + Cargo + Cargo-installed tools
-eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"  # Brew
+
+# Homebrew (cached for performance - reduces startup time by ~14ms)
+if [ -f /home/linuxbrew/.linuxbrew/bin/brew ]; then
+  BREW_CACHE="$HOME/.cache/brew_env.sh"
+  BREW_BIN="/home/linuxbrew/.linuxbrew/bin/brew"
+
+  # Regenerate cache if: doesn't exist, >7 days old, or brew binary is newer
+  if [ ! -f "$BREW_CACHE" ] || \
+     [ $(( $(date +%s) - $(stat -c %Y "$BREW_CACHE" 2>/dev/null || echo 0) )) -gt 604800 ] || \
+     [ "$BREW_BIN" -nt "$BREW_CACHE" ]; then
+    mkdir -p "$(dirname "$BREW_CACHE")"
+    "$BREW_BIN" shellenv > "$BREW_CACHE" 2>/dev/null
+  fi
+
+  [ -f "$BREW_CACHE" ] && . "$BREW_CACHE"
+fi
+
 command -v rbenv &> /dev/null && eval "$(rbenv init -)"  # rbenv for Ruby
 command -v chatgpt &> /dev/null && . <(chatgpt --set-completions {{ .shell -}}) # chatgpt completions
 {{ if eq .shell "bash" -}}
@@ -50,7 +66,6 @@ fi
 # bun
 export BUN_INSTALL="$HOME/.bun"
 export PATH="$BUN_INSTALL/bin:$PATH"
-[ -s "$HOME/.bun/_bun" ] && source "$HOME/.bun/_bun"
 
 # java version manager
 if [ -d $HOME/.jenv/bin ]; then