add OSC7 SSH newterm support

Enhances the existing Alt+Enter newterm functionality to support
SSH connections via OSC7 working directory notifications.

- Parses OSC7 sequences in format file://[user@]hostname/path
- Launches new st terminal with SSH to remote directory
- Proper shell escaping for paths with spaces and special chars
- Falls back to local terminal on SSH failure or invalid paths
- Supports both user@hostname and hostname-only formats

README-OSC7-SSH.md

@@ -0,0 +1,132 @@
+# ST OSC7 SSH Enhancement Patch
+
+This patch enhances the existing Alt+Enter new terminal functionality in st to support SSH connections via OSC7 (Operating System Command 7) working directory notifications.
+
+## Features
+
+- **OSC7 Support**: Adds handling for OSC7 escape sequences to track working directory
+- **SSH Detection**: Automatically detects when you're in an SSH session based on OSC7 hostname
+- **Smart Terminal Launch**: Alt+Enter launches appropriate terminal:
+  - **Remote SSH**: If connected via SSH, opens new terminal with SSH connection to same directory
+  - **Local Directory**: If local session, uses OSC7 directory or falls back to pid-based method
+
+## Installation
+
+1. Apply the patch to your st source:
+```bash
+patch -p1 < st-osc7-ssh-newterm.patch
+```
+
+2. Recompile and install st:
+```bash
+make clean && make && sudo make install
+```
+
+## Shell Setup
+
+To enable OSC7 support, add this to your shell configuration:
+
+### For Bash (~/.bashrc)
+```bash
+# OSC7 working directory notification
+osc7_cwd() {
+    local hostname="${HOSTNAME:-$(hostname)}"
+    local username="${USER:-$(whoami)}"
+    printf '\033]7;file://%s@%s%s\033\\' "$username" "$hostname" "$PWD"
+}
+
+# Update working directory after each command
+if [[ "$TERM" == st* ]]; then
+    PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND$'\n'}osc7_cwd"
+fi
+```
+
+### For Zsh (~/.zshrc)
+```bash
+# OSC7 working directory notification
+osc7_cwd() {
+    local hostname="${HOSTNAME:-$(hostname)}"
+    local username="${USER:-$(whoami)}"
+    printf '\033]7;file://%s@%s%s\033\\' "$username" "$hostname" "$PWD"
+}
+
+# Update working directory after each command
+if [[ "$TERM" == st* ]]; then
+    precmd_functions+=(osc7_cwd)
+fi
+```
+
+### For Fish (~/.config/fish/config.fish)
+```fish
+# OSC7 working directory notification
+function osc7_cwd
+    set hostname (hostname)
+    set username (whoami)
+    printf '\033]7;file://%s@%s%s\033\\' $username $hostname $PWD
+end
+
+# Update working directory after each command
+if string match -q "st*" $TERM
+    function __osc7_cwd_handler --on-event fish_prompt
+        osc7_cwd
+    end
+end
+```
+
+## Usage
+
+1. **SSH to a remote server** with OSC7-enabled shell setup
+2. **Navigate to any directory** on the remote server
+3. **Press Alt+Enter** to launch a new terminal
+
+The new terminal will automatically:
+- Connect via SSH to the same remote server
+- Change to the same working directory
+- Use your default shell
+
+## Technical Details
+
+### OSC7 Format
+The patch handles OSC7 sequences in the format:
+```
+ESC]7;file://hostname/path/to/directory ESC\
+```
+
+### SSH Command Generation
+When launching a remote terminal, the patch constructs:
+```bash
+ssh -t user@hostname "cd /path/to/directory && exec $SHELL"
+```
+
+### Fallback Behavior
+- If SSH connection fails, falls back to local terminal
+- If OSC7 directory is inaccessible, uses original pid-based directory detection
+- If no OSC7 data available, uses original behavior
+
+## Troubleshooting
+
+1. **Alt+Enter opens local terminal instead of SSH**:
+   - Ensure shell is sending OSC7 sequences
+   - Check that hostname in OSC7 is not "localhost"
+
+2. **SSH connection fails**:
+   - Verify SSH key authentication is set up
+   - Check that remote server allows SSH connections
+   - Patch will fall back to local terminal on SSH failure
+
+3. **Wrong directory opened**:
+   - Ensure OSC7 sequences are being sent after directory changes
+   - Check shell configuration for OSC7 setup
+
+## Compatibility
+
+- Requires existing newterm patch (Alt+Enter functionality)
+- Works with any SSH-accessible remote server
+- Compatible with bash, zsh, fish, and other shells that support prompt customization
+
+## Security Considerations
+
+- Uses existing SSH configuration and keys
+- No additional authentication required
+- Falls back gracefully on connection failures
+- Only connects to hosts specified in OSC7 sequences