New agents and instructions for AI have been added

.github/instructions/bash-scripts.instructions.md

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+---
+description: "Use when writing or editing shell scripts in tools/, src/bin/, or src/infrastructure/. Covers bash conventions for XC_VM."
+applyTo: "**/*.sh"
+---
+# Bash Script Conventions — XC_VM
+
+## Required Header
+```bash
+#!/bin/bash
+set -euo pipefail
+```
+
+## Style
+- Indent with 4 spaces (not tabs — unlike PHP)
+- Quote all variables: `"$var"` not `$var`
+- Use `[[ ]]` for conditionals, not `[ ]`
+- Use `$()` for command substitution, not backticks
+
+## Error Handling
+- `set -e` — exit on first error
+- `set -u` — treat unset variables as error
+- `set -o pipefail` — catch errors in pipes
+- Use `trap` for cleanup on exit when creating temp files
+
+## Security
+- Never pass secrets via command-line arguments (visible in `ps`)
+- Use environment variables or files with restricted permissions (0600)
+- Validate external input before using in commands
+- Avoid `eval` unless absolutely necessary
+
+## Paths
+- Use absolute paths for system binaries: `/usr/bin/php8.2`, `/usr/sbin/nginx`
+- Reference project root via variable, not hardcoded paths