F-05.11 Standalone repo extraction (post-v0.2)

[tiana-code]

Extract decision-engine into tiana-code/decision-engine after v0.2 (library + service). Tracking only; not started until v0.2 ships.

Part of #163 (E-05 Decision Engine).

[tiana-code]

Status: the library is extraction-ready.

• libs/decision-engine is self-contained: it depends only on kotlin-stdlib and jackson-databind, with no project() dependencies on other modules, so it moves to a standalone repo cleanly.
• It is already publishable (maven-publish, com.fincore:decision-engine), proven by the in-tree library-embedding test.

Extraction plan (owner-driven, since it crosses the delivery boundary):

1. Create the public repo tiana-code/decision-engine (new public repo - owner action).
2. Move libs/decision-engine source and its build there; keep com.fincore:decision-engine coordinates.
3. Publish to a Maven registry (publish - owner action).
4. Rewire the three in-tree consumers (services/decision, services/compliance, services/payments) from project(":libs:decision-engine") to the published artifact, and drop the module from settings.gradle.kts.

Steps 1 and 3 are the only blockers and are owner-only. Steps 2 and 4 are mechanical once the repo exists; I can prepare that change when you are ready. Keeping this open under v0.3.0.

[tiana-code]

Standalone repo is live: https://github.com/tiana-code/decision-engine (public, CI green).

Done:

• Extracted libs/decision-engine into a self-contained Gradle project (own wrapper, build, detekt/spotless config, CI). 35 files, source only, no build artifacts.
• Clean build verified: compile, spotless, detekt, and the full test suite pass standalone.
• README, BSL-1.1 LICENSE, and repo description written (no AI-tells, SEO-oriented).

Remaining follow-ups (owner-gated):

1. Publish com.fincore:decision-engine to a Maven registry (publish step).
2. Once published, rewire the three in-tree consumers (services/decision, services/compliance, services/payments) from project(":libs:decision-engine") to the published artifact, then drop the module from the umbrella settings.gradle.kts.

Until then the umbrella keeps its in-tree module (the build stays green); the standalone repo is the publishable home. Keeping this open for the publish + rewire.