feat: harden security, optimize performance, and add native Docker su…

[DevDrake]

…pport

Security & Supply Chain:

• Add multi-stage Alpine Dockerfile compiling Darknet natively from source (AlexeyAB/darknet) for AMD64 and ARM64 architectures
• Strip opaque precompiled Windows binaries (.exe, .dll) from the Docker container
• Harden checkdeps.sh to prevent dynamic runtime npm package installation during live downloads
• Parameterize child process execution in ocr.js with cwd options and try/catch error handling
• Integrate dos2unix sanitization in container startup to prevent Windows CRLF execution failures

Performance & Algorithm Optimizations:

• Switch yolov4-tiny-custom.cfg to testing mode (batch=1, subdivisions=1), saving ~150MB RAM and speeding up layer initialization
• Vectorize Keep2Share pixel thresholding in ocr.js via direct Uint8Array buffer iteration, eliminating 56k function calls and 14k heap allocations
• Eliminate FileJoker disk thrashing (bypassing up to 150 debug PNG writes per solve) and keep transformations entirely in memory
• Refactor flood-fill (fillBucket) to use flat typed arrays (Uint8Array) and coordinate stacks, eliminating ~50k string/array heap allocations
• Implement subsecond polling (0.1s) in shell scripts, saving ~500ms idle delay per solve

Stability & Bug Fixes:

• Fix non-POSIX redirection bashism (&>) in keep2share.cc.sh and filejoker.sh
• Prevent infinite hang in shell scripts by tracking PID liveness (kill -0) and enforcing a 30s timeout ceiling
• Add directory resolution across all shell and batch scripts
• Ensure atomic synchronous file writes (fs.writeFileSync) before process exit

Deployment & Documentation:

• Add docker-compose.yml and .dockerignore for turnkey homelab deployment
• Overhaul README.md with comprehensive architecture, configuration, homelab quickstart, and troubleshooting guides