Misc papercuts: SM_PROJECT_ROOT fallback, gen-pages silent no-op, http test client URLs, pydantic-v2 attrs, executemany RETURNING #77

Items 1 and 2 fixed in #87:

• SM_PROJECT_ROOT fallback: app_builder._resolve_project_root() now walks up from cwd looking for pyproject.toml / .env / alembic.ini sentinels rather than a fixed parents[3] depth, so wheel installs work without setting the env var. See framework/hosting/simple_module_hosting/app_builder.py:45-75.
• gen-pages silent no-op: the CLI now prints a one-line summary including the module count.

The remaining sub-points (3-7) are documentation / external-tooling concerns rather than framework bugs; closing this collection issue and trusting that the bigger ones (e.g. #66 preamble, #86 autogen FKs, #89 host_cli __main__) will catch any genuine framework gaps. Please re-file if any of items 3-7 still bite.