[AZ-266] [AZ-269] [AZ-277] [AZ-280] Cross-cutting log/config + SE3/SHA256 helpers

AZ-266: schema-compliant JSON logging entrypoint, level normalisation,
handler-topology guard, format-error fallback (log_record_schema v1.0.0).
AZ-269: env > YAML > defaults config loader, frozen Config dataclass,
missing-var fail-fast with pointer to .env.example, component-block registry.
AZ-277: GTSAM-backed SE3Utils (matrix<->SE3 + exp/log/adjoint) with strict
orthogonality, dtype, and bottom-row contract enforcement.
AZ-280: atomicwrites-backed write_atomic + independent verify +
order-deterministic aggregate_hash; sidecar format strictness.
pyproject.toml pins gtsam>=4.2,<5.0 and atomicwrites>=1.4,<2.0
(named-backend deps per the AZ-277 / AZ-280 contracts).
139 unit tests pass (44 new). Review verdict: PASS_WITH_WARNINGS;
findings are perf-NFR + journald deferrals, no blocking issues.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/gps_denied_onboard/config/schema.py

@@ -1,26 +1,157 @@
-"""Config dataclass schemas — STUB.
+"""Config dataclasses for E-CC-CONF (AZ-269 / AZ-246).
 
-Concrete YAML schema is owned by AZ-269. Bootstrap declares only the runtime-level
-config container so the composition root can type its `compose_*` signatures.
+The outer `Config` aggregates one frozen nested dataclass per top-level
+config block. Cross-cutting blocks (`log`, `fdr`, `runtime`) live here;
+per-component blocks live with their own component epic and are
+registered into `Config.components` via `register_component_block`.
+
+Public surface frozen by `_docs/02_document/contracts/shared_config/composition_root_protocol.md` v1.0.0.
 """
 
 from __future__ import annotations
 
-from dataclasses import dataclass, field
-from typing import Any
+from collections.abc import Mapping
+from dataclasses import dataclass, field, fields, is_dataclass, replace
+from typing import Any, Final
+
+__all__ = [
+    "Config",
+    "ConfigError",
+    "FdrConfig",
+    "LogConfig",
+    "RequiredFieldMissingError",
+    "RuntimeConfig",
+    "register_component_block",
+]
+
+
+class ConfigError(RuntimeError):
+    """Base class for all config-loader errors that should reach the caller."""
+
+
+class RequiredFieldMissingError(ConfigError):
+    """Raised when a required configuration value is absent from env + YAML + defaults.
+
+    Always names the missing variable and points at the runtime helper that
+    documents the full set (``.env.example``).
+    """
+
+
+@dataclass(frozen=True)
+class LogConfig:
+    """Cross-cutting logging block (E-CC-LOG)."""
+
+    level: str = "INFO"
+    tier: int = 1
+    sink: str = "console"
+
+
+@dataclass(frozen=True)
+class FdrConfig:
+    """Cross-cutting Flight Data Recorder block (E-CC-FDR-CLIENT / AZ-247).
+
+    The producer-side ring-buffer fields below are documented defaults
+    consumed by AZ-273; only the outer container is owned by AZ-269.
+    """
+
+    queue_size: int = 4096
+    overrun_policy: str = "drop_oldest"
+    path: str = "/var/lib/gps-denied/fdr"
 
 
 @dataclass(frozen=True)
 class RuntimeConfig:
-    """Runtime configuration loaded from YAML + env vars.
-
-    The concrete field set is filled in by AZ-269. This stub is enough for the
-    composition root + tests to import the type.
-    """
+    """Top-level runtime descriptors that don't belong to a single component."""
 
     fc_profile: str = "ardupilot_plane"
     tier: int = 1
     db_url: str = ""
-    log_level: str = "INFO"
-    log_sink: str = "console"
-    extras: dict[str, Any] = field(default_factory=dict)
+    camera_calibration_path: str = ""
+    inference_backend: str = "pytorch_fp16"
+    tile_cache_path: str = "/var/lib/gps-denied/tiles"
+
+
+# Documented defaults for cross-cutting blocks ONLY. Per-component defaults
+# live with their own component epic. The registry below is the single
+# source of truth so two components cannot silently claim the same key.
+_DEFAULT_BLOCKS: Final[dict[str, type]] = {
+    "log": LogConfig,
+    "fdr": FdrConfig,
+    "runtime": RuntimeConfig,
+}
+
+
+# Registry for per-component nested dataclasses. Each component epic
+# calls ``register_component_block("c5_state", C5StateConfig)`` from its
+# package import path; the composition root drives those imports before
+# calling ``load_config``.
+_COMPONENT_REGISTRY: dict[str, type] = {}
+
+
+def register_component_block(slug: str, dataclass_type: type) -> None:
+    """Register a per-component frozen dataclass under its component slug."""
+    if not is_dataclass(dataclass_type):
+        raise TypeError(
+            f"register_component_block({slug!r}, ...): block must be a dataclass; "
+            f"got {dataclass_type!r}"
+        )
+    existing = _COMPONENT_REGISTRY.get(slug)
+    if existing is not None and existing is not dataclass_type:
+        raise ConfigError(
+            f"duplicate component config registration for slug {slug!r}: "
+            f"{existing!r} vs {dataclass_type!r}"
+        )
+    _COMPONENT_REGISTRY[slug] = dataclass_type
+
+
+def _resolve_default_blocks() -> dict[str, Any]:
+    """Instantiate every documented cross-cutting block with its defaults."""
+    return {name: cls() for name, cls in _DEFAULT_BLOCKS.items()}
+
+
+def _resolve_component_blocks() -> dict[str, Any]:
+    """Instantiate every registered per-component block with its defaults."""
+    return {slug: cls() for slug, cls in _COMPONENT_REGISTRY.items()}
+
+
+@dataclass(frozen=True)
+class Config:
+    """Outer composition-root config (frozen end-to-end).
+
+    Components consume only their own slice via ``config.components[slug]``;
+    the runtime / log / fdr cross-cutting blocks are read directly via
+    attribute access by the composition root.
+    """
+
+    runtime: RuntimeConfig = field(default_factory=RuntimeConfig)
+    log: LogConfig = field(default_factory=LogConfig)
+    fdr: FdrConfig = field(default_factory=FdrConfig)
+    components: Mapping[str, Any] = field(default_factory=dict)
+
+    @classmethod
+    def with_blocks(cls, **blocks: Any) -> Config:
+        """Build a `Config` from a flat name-to-instance map.
+
+        Cross-cutting names (``log``, ``fdr``, ``runtime``) become attributes;
+        every other key is treated as a component slug and goes into
+        ``components``.
+        """
+        runtime = blocks.pop("runtime", RuntimeConfig())
+        log = blocks.pop("log", LogConfig())
+        fdr = blocks.pop("fdr", FdrConfig())
+        return cls(runtime=runtime, log=log, fdr=fdr, components=dict(blocks))
+
+
+def _block_field_names(block: Any) -> tuple[str, ...]:
+    return tuple(f.name for f in fields(block))
+
+
+def _replace_block(block: Any, overrides: Mapping[str, Any]) -> Any:
+    """Return ``replace(block, **overrides)`` after filtering unknown keys."""
+    if not overrides:
+        return block
+    known = set(_block_field_names(block))
+    filtered = {k: v for k, v in overrides.items() if k in known}
+    if not filtered:
+        return block
+    return replace(block, **filtered)