manifest/__init__.py was a facade that eagerly imported every piece (agent,
bottle, egress, git, loader, schema, util) and defined the aggregate Manifest /
ManifestIndex, so importing a leaf like `manifest.util` paid 19 modules.
Move the aggregate model — Manifest, ManifestIndex, and the bottle-resolution
helpers — into manifest/index.py (which keeps the framework imports it needs),
and make __init__ a thin __getattr__ facade over the 12 __all__ names (mapping
each to its submodule), with a TYPE_CHECKING block. The package docstring is
preserved.
`import bot_bottle.manifest.util` drops 19 -> 3; the package itself is 2. All
`from bot_bottle.manifest import Manifest/ManifestIndex/ManifestError/…`
call-sites keep working via the lazy facade; no importer changes needed.
Full unit suite green (2243).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
