chore(release): prepare v0.1.11

[chaliy]

Summary

• Bump version to 0.1.11
• Update CHANGELOG with all 50 changes since v0.1.10

Release Highlights

• Second external contribution by @shubham-lohiya — Bash class with Monty Python execution and external function handler (feat(python): expose Bash class with Monty Python execution and external function handler #760)
• Browser terminal example — bashkit running in the browser via WebAssembly (wasm32-wasip1-threads)
• New features: structured execution traces, per-instance memory budgets, static AST budget validation, head -c byte mode, IFS separator + $_ tracking
• Security hardening: 15 blackbox findings fixed, readonly bypass blocked, stack overflow/memory exhaustion/source recursion limits enforced
• Major refactoring: FileSystem core/ext split, shared ArgParser, register_builtins! macro, ShellRef Context API

Test plan

• cargo fmt --check passes
• cargo clippy --all-targets --all-features -- -D warnings passes
• cargo test --all-features passes
• CI green
• After merge, CI creates GitHub Release and publishes to crates.io/PyPI/npm