Agentic UCC add-on builder for Splunk

Building a Splunk add-on that actually passes **AppInspect** is normally a slow, expert-only loop: scaffold with `ucc-gen`, package it, run `splunk-appinspect`, read the findings, hand-fix the source, rebuild, re-inspect — repeat. UCC App Builder closes that loop with a tool-calling AI agent: you describe the add-on in chat, the agent edits the source files, grounds the design in your **live Splunk** (real indexes/sourcetypes/SPL, via read-only MCP tools you approve), then **builds → runs AppInspect → self-corrects → repeats until the package is AppInspect-clean**, showing the whole trace inline as it goes. It ships as a fully self-contained native Splunk app — no Node sidecar. Everything the embedded IDE needs (build, AppInspect, the LLM proxy, an input emulator) runs in Splunk's own Python via persistent REST handlers, with `ucc-gen` and AppInspect vendored into the app itself.