Documentation had drifted behind the post-0.8.0 work. Adds a CHANGELOG [Unreleased] section, documents the three new feature flags in the config reference (and removes the retired ROBOCO_RAG_USE_HYDE), a new Architectural Conventions Standard page, the provider-overload break in CLAUDE.md, the >=3.13 Python floor + feature flags in the README, and the toolchain/conventions delivery gates + structured-note model across the developer / QA / PR-reviewer role docs and the task-model doc.
