feat(BA-4361): Add entity graph and scope-entity type converters

[fregataa]

resolves #8738 (BA-4361)

Summary

• Add ENTITY_GRAPH dict with exhaustive match/case over all EntityType values
• Add get_relation_type() helper for parent-child edge lookup
• Add scope_type_to_entity_type() / entity_type_to_scope_type() converters
• Add InvalidTypeConversionError exception
• Add SCOPE_TO_ENTITY_MAP / ENTITY_TO_SCOPE_MAP constants
• Add missing EntityType values (STORAGE_HOST, KEYPAIR, NETWORK, KERNEL_SCHEDULING_HISTORY, DEPLOYMENT_AUTO_SCALING_POLICY, VFOLDER_PERMISSION, USER_ROLE)

[Copilot]

Pull request overview

Adds shared permission-type utilities to support RBAC entity relationships and conversions between ScopeType and EntityType, along with corresponding unit tests.

Changes:

• Introduces an ENTITY_GRAPH describing parent→child entity edges and a get_relation_type() helper.
• Adds scope_type_to_entity_type() / entity_type_to_scope_type() converters plus InvalidTypeConversionError.
• Expands EntityType with several missing values and re-exports new APIs through manager permission types; adds unit tests.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

File	Description
tests/unit/manager/rbac/test_permission_types.py	Adds tests for ENTITY_GRAPH, relation lookup helper, and scope/entity converters.
src/ai/backend/manager/data/permission/types.py	Re-exports new common permission graph/mapping utilities for manager-side imports.
src/ai/backend/common/data/permission/types.py	Implements entity graph, relation lookup helper, scope/entity converters, and adds new EntityType values.
src/ai/backend/common/data/permission/exceptions.py	Adds InvalidTypeConversionError exception type.

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[Copilot]

_get_entity_children() is annotated to always return dict[...], but the match statement has no default (case _) branch. If a new EntityType is added and not handled here, Python will return None, and ENTITY_GRAPH will silently contain an invalid value until a later TypeError. Add an explicit default case that raises (e.g., AssertionError/NotImplementedError) to fail fast and preserve the intended exhaustiveness guarantee.

[Copilot]

scope_type_to_entity_type() uses match without a default branch. If a new ScopeType is added and not mapped, this function will implicitly return None, which then propagates into SCOPE_TO_ENTITY_MAP during module import. Add a case _ branch that raises InvalidTypeConversionError (or a dedicated exception) so unmapped scope types fail fast with a clear message.

[Copilot]

test_no_self_referencing_edges and test_every_edge_has_distinct_parent_and_child assert the same condition (parent != child). Consider removing one to avoid redundant coverage and keep the test suite lean.

Suggested change

	def test_every_edge_has_distinct_parent_and_child(self) -> None:
	for parent, children in ENTITY_GRAPH.items():
	for child in children:
	assert parent != child, f"Self-referencing edge: {parent}"

[Copilot]

EntityType values are persisted in RBAC tables using StrEnumType(EntityType, length=32) (e.g., association_scopes_entities / object_permissions). The new value "session:kernel:scheduling_history" is 33 chars long, which will overflow the DB column size and can cause truncation or DB errors when stored. Either shorten this enum value to fit within 32 chars, or widen the related DB columns + alembic migrations and update the StrEnumType(..., length=...) usages accordingly.

Suggested change

	KERNEL_SCHEDULING_HISTORY = "session:kernel:scheduling_history"
	KERNEL_SCHEDULING_HISTORY = "session:kernel:sched_history"