feat(config): add core component config engine

[maxxgx]

Summary

• Introduces physicalai.config (@export_config, to_config, instantiate, normalization, envelope validation, cycle detection).
• Consolidates dotted-path importing under physicalai.config.importing; inference and robot transport re-export from there.
• Updates docs/reference/config-schema.md and adds unit tests under tests/unit/config/.

Test plan

• uv run pytest tests/unit/config/

Review & merge order

1. PR #202 — Core config engine (this PR) → main
   Core physicalai.config (export, instantiate, validation)

2. PR #204 — Robot drivers & SharedRobot transport
   Robot config export and SharedRobot owner process startup

3. PR #205 — Camera drivers & SharedCamera transport
   Camera config export and SharedCamera publisher startup

4. PR #206 — Runtime, InferenceModel & CLI
   End-to-end YAML, physicalai run --config, examples, and user docs

In parallel: PR #203 — Component config design doc → docs/design
Detailed design doc; not blocking the code PRs

[Copilot]

Pull request overview

Adds a new physicalai.config module that defines a strict, JSON-shaped component configuration format (class_path + init_args) along with utilities to export live components to config, validate/normalize configs, and instantiate trusted config trees. This centralizes dotted-path importing and updates documentation/tests to align Runtime configuration with the new core config engine.

Changes:

• Introduces physicalai.config public API (@export_config, to_config, instantiate, validation/normalization, YAML helpers, envelope validation).
• Consolidates dotted-path importing into physicalai.config.importing and re-exports it from inference and robot transport for backward compatibility.
• Updates the config schema reference docs and adds substantial unit test coverage for export/normalize/instantiate/YAML round-trips.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/unit/config/init.py	Marks the new config unit test package and sets ruff ignores.
tests/unit/config/test_component_config.py	Comprehensive tests for export/normalize/instantiate behavior, including error paths and depth/cycle guards.
tests/unit/config/test_yaml.py	Tests YAML serialization/deserialization round-trips for exported components/config mappings.
src/physicalai/config/init.py	Defines the public physicalai.config API surface and re-exports key functions/types.
src/physicalai/config/_envelope.py	Adds schema-positive envelope validation and component-config normalization for transports.
src/physicalai/config/_errors.py	Introduces config-specific error types (ComponentConfigError, ComponentImportError).
src/physicalai/config/_export.py	Implements @export_config, captured init-arg export via to_config, and class_path resolution.
src/physicalai/config/_instantiate.py	Implements trusted config preflight validation and recursive instantiation.
src/physicalai/config/_normalize.py	Implements recursive normalization, cycle/depth detection, and config-shape validation.
src/physicalai/config/_path.py	Adds shared path formatting helper for consistent error messages.
src/physicalai/config/_types.py	Defines core JSON/config TypedDicts and internal constants (depth limit, private attrs).
src/physicalai/config/_yaml.py	Adds YAML serialization/loading helpers for component configs.
src/physicalai/config/importing.py	New canonical dotted-path import helper used across config/inference/robot.
src/physicalai/inference/_importing.py	Re-exports canonical import_dotted_path for backward compatibility.
src/physicalai/robot/transport/_importing.py	Re-exports canonical import_dotted_path for backward compatibility.
docs/reference/config-schema.md	Updates documentation to describe the strict ComponentConfig schema and Runtime document shapes.