refactor(ogc): stabilize module boundaries

[thodson-usgs]

Commit

This branch is based directly on main at 44f2aeec and contains one commit:

• 69a9d1bd — refactor(ogc): stabilize module boundaries

Summary

• move OgcDialect and endpoint defaults into the low-level ogc.policy leaf
• move argument normalization, request construction, and queryables/schema lookup into ogc.requests
• keep pagination and sync/async orchestration in ogc.engine, with a frozen compatibility surface for previous private imports
• remove shaping-to-engine dependencies and enforce an acyclic OGC runtime graph
• expose a four-symbol OGC service-adapter facade and route NGWMN through it exclusively
• stop using waterdata.utils as a bulk re-export of private OGC helpers
• scope API_USGS_PAT to api.waterdata.usgs.gov, including stripping it before sync or async cross-host redirects
• update ADR 0003, the current-state architecture overview, NEWS, and executable fitness functions

Why

The architecture baseline identified private cross-package contracts, a logical
ogc.engine/ogc.shaping cycle, and generic OGC requests that could receive
Water Data credentials without considering the destination host. This change
stabilizes those existing boundaries without introducing the separate
API-neutral transport layer in downstream PR #350.

Compatibility

Public service imports, function signatures, return shapes, metadata,
deprecations, pagination, chunking, retry, and resume behavior are unchanged.
Previous underscore-prefixed OGC paths remain available where compatibility is
required, and an architecture fitness function prevents that legacy surface
from expanding.

Validation

• full suite: 636 passed with 56 expected warnings
• coverage: 97%
• all configured pre-commit hooks passed, including Ruff and strict mypy
• Sphinx HTML build passed with the same four pre-existing warnings
• isolated wheel build/install/import outside the checkout passed; includes ogc.policy and ogc.requests
• exact four-symbol OGC facade verified from the installed wheel
• complete GitHub Actions matrix previously passed; refreshed checks are running on the squashed commit

Scope

This PR stabilizes existing OGC boundaries. API-neutral transport extraction
and migration of Water Use away from private OGC pagination are isolated in
stacked draft PR #350.