refactor: Make QueryBlocklistRule an interface for extensibility

[abhishekrb19]

Summary

• Converts QueryBlocklistRule from a concrete class to an interface with two methods: getRuleName() and matches(Query<?>).
• Moves the existing implementation to DefaultQueryBlocklistRule with a default impl on the interface @JsonTypeInfo(defaultImpl = DefaultQueryBlocklistRule.class) so existing JSON configs without a "type" field continue to deserialize correctly.
• Extensions can register new rule types as Jackson subtypes via SimpleModule.registerSubtypes(...) and we can even introduce new union rule types with different logic w/o polluting existing default implementation.

Motivation

The current blocklist logic is fixed to datasource/queryType/context matching. Making it an interface allows adding new rule types (e.g., regex-based, time-window-based, user-based) without modifying the existing code.

This PR has:

• been self-reviewed.
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[FrankChen021]

Severity	Findings
P0	0
P1	0
P2	1
P3	0
Total	1

Reviewed 7 of 7 changed files.

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This is an automated review by Codex GPT-5.5

[FrankChen021]

[P2] Fail unknown blocklist rule types instead of defaulting

Using defaultImpl = DefaultQueryBlocklistRule.class makes Jackson use the default rule not only when type is absent, but also when a non-empty type id cannot be resolved. For the new extension point, a broker or coordinator that lacks a registered custom rule subtype can silently deserialize that rule as DefaultQueryBlocklistRule; with Druid's unknown-property-tolerant mapper, extension-specific fields are ignored and any standard fields such as dataSources can turn into a broader block than intended. Please distinguish the legacy missing-type case from an unrecognized explicit type, so unknown extension rules fail fast rather than being interpreted as default rules.