install.sh: install Claude Code if not already present

Adds a step after personal-dotfile deploy that runs Anthropic's
official one-liner installer (curl -fsSL https://claude.ai/install.sh | bash)
when no 'claude' binary is found. No-ops if claude is already on the
machine. Opt out with DRUNKENDOTFILES_SKIP_CLAUDE=1. Install failures
are non-fatal — the rest of the flow still completes.

README: document the new step + the opt-out env var + curl in the
required tools list.

install.sh

@@ -110,10 +110,26 @@ for f in "${PERSONAL_FILES[@]}"; do deploy_one "$f"; done
 for d in "${PERSONAL_DIRS[@]}"; do deploy_one "$d"; done
 
 # .local/bin/claude is a relative symlink to ../share/claude/versions/...
-# If that target isn't present on this machine, remove the dangling link.
+# If that target isn't present on this machine, remove the dangling link so
+# Claude Code's own installer (next step) can manage it.
 if [ -L "$HOME/.local/bin/claude" ] && [ ! -e "$HOME/.local/bin/claude" ]; then
   rm "$HOME/.local/bin/claude"
-  info "(skipped .local/bin/claude: target not present on this machine)"
+fi
+
+# 4. Install Claude Code (Anthropic's CLI). Skip if already installed or
+# explicitly opted out via DRUNKENDOTFILES_SKIP_CLAUDE=1.
+if [ "${DRUNKENDOTFILES_SKIP_CLAUDE:-0}" = "1" ]; then
+  info "Skipping Claude Code install (DRUNKENDOTFILES_SKIP_CLAUDE=1)"
+elif have claude || [ -x "$HOME/.local/bin/claude" ]; then
+  info "Claude Code already installed ($(claude --version 2>/dev/null || echo 'version unknown'))"
+else
+  log "Installing Claude Code"
+  if have curl; then
+    curl -fsSL https://claude.ai/install.sh | bash \
+      || warn "Claude Code install failed; continuing. Install manually with: curl -fsSL https://claude.ai/install.sh | bash"
+  else
+    warn "curl not found; skipping Claude Code install"
+  fi
 fi
 
 # Ensure +x on user scripts