Feature/lua scripting

[highbyte]

Add Lua scripting support

Adds a Lua scripting engine to the emulator, exposed in the Avalonia Desktop and Browser host apps. Scripts run as coroutines alongside the emulator and can read/write CPU registers and memory, inject input, observe emulator state, and control the emulator lifecycle — enabling automation, TAS-style input playback, and in-emulator tooling without modifying the core.

Scripting model

Two styles can be mixed in a single script:

• Linear loop (BizHawk-style): top-level while true do … emu.frameadvance() end — reads like a sequential program, suspends on each frame
• Event hooks: global callbacks (on_before_frame(), on_started(), on_stopped(), etc.) called at specific emulator lifecycle points

Powered by MoonSharp, with AOT-compatible configuration for the WASM/Browser target.

Lua API surface

Domain	Highlights
Emulator control	emu.start/pause/stop/reset/select/quit(), emu.config_valid()
Queries	emu.state(), emu.framecount(), emu.time(), emu.selected_system/variant()
CPU	Read-only access to all registers and flags via cpu.*
Memory	mem.read(addr) / mem.write(addr, val) — routes through the same address decoding as the emulated CPU
Input	Keyboard and joystick state query + synthetic injection (input.key_press, input.joystick_set, etc.)
HTTP	Async GET/POST via http.* (works in both Desktop and Browser)
File I/O	file.* read/write with configurable base-directory sandboxing (Desktop only)
TCP client	tcp.* (Desktop only, opt-in)
Store	Cross-platform key/value persistence — filesystem on Desktop, localStorage in Browser

C64-specific integrations

• Type text into BASIC directly from Lua
• Load .d64 disk images at runtime

Host app integration

Desktop:

• Scripts loaded from a configurable directory (appsettings.json)
• --script <file> CLI argument to load and run a single script on startup (useful for CI/automation pipelines)
• Scripts tab shows directory path with an "open in file manager" button and a refresh button

Browser:

• In-app script editor (add, edit, delete) backed by localStorage
• AOT-safe MoonSharp configuration
• store API backed by localStorage instead of the filesystem

Scripts tab UI

Both apps show a Scripts tab with live status for all loaded scripts:

• Status dot (green / red / grey), enable/disable toggle, per-script reload button
• Columns: script name, status, yield type, registered hooks
• Column headers are clickable to sort by any column (ascending/descending toggle)
• Tab header shows active count; turns red when any script is system-disabled (syntax or runtime error)
• Scripts that error during execution are automatically disabled and flagged

Configuration

All behaviour is controlled via appsettings.json under Highbyte.DotNet6502.Scripting: master enable switch, script directory, per-feature allow-flags (AllowFileIO, AllowHttpRequests, AllowTcpClient, AllowStore), execution warning threshold, and runaway-script instruction limit.

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud