[AI-FSSDK] [FSSDK-12369] Add local holdouts support with includedRules field

[Mat001]

Summary

This PR adds local holdouts support to the Java SDK, allowing holdouts to target specific rules within a flag via an includedRules field.

Jira Ticket: FSSDK-12369

Changes

Core Model

• Holdout.java: Added includedRules field (List<String>, nullable). Null = global holdout (applies to all rules); non-null = local holdout (applies to specific rule IDs). Added getIncludedRules() and isGlobal() methods.

Configuration

• HoldoutConfig.java: Added globalHoldouts list and ruleHoldoutsMap (Map<String, List<Holdout>>). updateHoldoutMapping() now separates global vs local holdouts during initialization. Added getGlobalHoldouts() and getHoldoutsForRule(ruleId). Deprecated getHoldoutForFlag() (now delegates to getGlobalHoldouts()).
• ProjectConfig.java (interface): Added getGlobalHoldouts() and getHoldoutsForRule(String ruleId).
• DatafileProjectConfig.java: Added delegating implementations of both new interface methods.

Decision Logic

• DecisionService.java: Updated getVariationFromFlag() to use getGlobalHoldouts() instead of getHoldoutForFlag(). Added local holdout checks in getVariationFromExperimentRule() and delivery rule evaluation — checked after forced decisions, before regular bucketing.

JSON Parsers (all 4 updated)

• GsonHelpers.java: Parses optional includedRules JSON array into List<String>, null when absent.
• JsonConfigParser.java (Jackson): @JsonProperty("includedRules") already handled by @JsonCreator constructor.
• JsonSimpleConfigParser.java: Parses optional includedRules JSON array into List<String>, null when absent.

Tests

• HoldoutConfigTest.java: Expanded with 15+ tests covering global holdouts, local holdouts, mixed scenarios, backward compatibility (old datafiles with no includedRules default to global behavior), and isGlobal() semantics.

Decision Flow

Flag evaluation
  └── Global holdouts (includedRules == null) → checked at flag level
        └── If not in global holdout:
              └── Forced decisions → checked per rule
                    └── Local holdouts (includedRules != null) → checked per rule
                          └── Regular bucketing

Backward Compatibility

Old datafiles without includedRules default to null → isGlobal() == true → behave exactly as before.

🤖 Generated with Claude Code

[Mat001]

Closing as part of cleanup for FSSDK-12369.