release: cut v0.2.15 for explainability, scenario simulation & ops control center

[w7-mgfcode]

Tracking issue for the dev → main release that release-please will tag as v0.2.15 (pre-1.0 PATCH bump; 49 commits since v0.2.14, all feat:/fix:, no breaking changes).

User-facing changes since v0.2.14

• Forecast Explainability & Driver Attribution slice — /explain/{forecast,runs,jobs} + ExplanationPanel UI (Forecast Explainability & Driver Attribution slice #224)
• Scenario Simulation / What-If Planning — full version (Scenario Simulation / What-If Planning — Full Version #223) on top of the MVP slice (Scenario Simulation / What-If Planning (MVP) — new scenarios slice #221)
• ForecastOps Control Center — full model-health/drift/incident/action layer (feat: ForecastOps Control Center — Full Version (model health & drift, incident export, action layer) #219) on the read-only ops slice (feat: ForecastOps Control Center — read-only ops slice + /ops page #217)
• RAG project-docs indexing (RAG Corpus Manager (MVP): one-click bulk-index of bundled project docs #214) + bundled ForecastLab user guides (docs: add ForecastLab user-facing guides and curate the RAG corpus to user docs #216)
• Light/dark theme redesign for cohesion and accessibility (feat(ui): redesign light and dark theme for cohesion and accessibility #210)
• fix(ui): parse application/problem+json error bodies (fix(ui): api client never parses application/problem+json error bodies #230)

Process

• dev → main PR titled feat(release): so the merge-commit subject triggers the release-please bump.
• Merge the release-please Release PR on main to tag v0.2.15.
• Back-merge main → dev with a merge commit.

[w7-mgfcode]

Released v0.2.15 — tag pushed, GitHub Release published (forecastlabai-0.2.15 wheel + sdist), cd-release.yml green. dev→main #233, Release PR #234, back-merge main→dev #235 all merged; main is an ancestor of dev.