feat: implement classic layout, local demo/mock mode, and piped update.sh

- Replace the 2x2 agent grid dashboard with a beautiful monochrome scrollable 'Classic Chat Mode' as default.
- Support layout/UI toggling via `/layout` or `/ui`.
- Implement a fully local offline 'demo' / 'mock' LLM provider for instant play out-of-the-box.
- Prompt unconfigured clients on startup to choose either Demo mode or setup real API keys.
- Develop dynamic directory-resolving `update.sh` to allow stdin/pipe curl-execution instantly from anywhere.
- Add piped update one-liner in the README file.

Author: Chintanpatel24

README.md

@@ -85,10 +85,10 @@ bun link          # optional global arrowcode / ac
 
 ### Update
 
-To update ArrowCode while preserving any local modifications you have made:
+To instantly update ArrowCode from any directory, keeping your local changes preserved:
 
 ```bash
-./update.sh
+curl -fsSL https://raw.githubusercontent.com/Chintanpatel24/arrowcode/main/update.sh | bash
 ```
 
 ### Setup API key

update.sh

@@ -13,8 +13,30 @@ log()  { printf '%s==>%s %s\n' "$CYN" "$RST" "$*"; }
 ok()   { printf '%s[ok]%s %s\n' "$GRN" "$RST" "$*"; }
 err()  { printf '%s[err]%s %s\n' "$RED" "$RST" "$*" >&2; }
 
-# Find ArrowCode base directory
-DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# Find ArrowCode base directory dynamically (even if piped via stdin)
+if [ -n "${BASH_SOURCE[0]:-}" ] && [ -f "${BASH_SOURCE[0]}" ]; then
+  DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+else
+  # fallback to global/local shared locations if piped via stdin
+  DIR="${ARROWCODE_DIR:-$HOME/.local/share/arrowcode}"
+fi
+
+if [ ! -d "$DIR" ] || [ ! -f "$DIR/package.json" ]; then
+  # Try to find base from command line 'arrowcode' binary symlink or standard home folder
+  if command -v arrowcode >/dev/null 2>&1; then
+    BIN_PATH=$(which arrowcode)
+    if [ -h "$BIN_PATH" ]; then
+      REAL_BIN=$(readlink "$BIN_PATH")
+      DIR="$(cd "$(dirname "$REAL_BIN")/.." && pwd)"
+    fi
+  fi
+fi
+
+if [ ! -d "$DIR" ] || [ ! -f "$DIR/package.json" ]; then
+  err "Could not find ArrowCode installation directory. Please run the installer first or set ARROWCODE_DIR."
+  exit 1
+fi
+
 cd "$DIR"
 
 log "Updating ArrowCode at $DIR..."