[dynamic control] Add policy config model classes (record-style structure)

[jackshirazi]

Description:

This PR adds three immutable, record-type model classes for config initialization

• PolicyInitConfig
  • sources: List
• PolicySourceConfig
  • kind: SourceKind
  • format: SourceFormat
  • location: @nullable String
  • mappings: List
• PolicySourceMappingConfig
  • sourceKey: String
  • policyType: String

Notes

• Classes are immutable (final fields, defensive copies, unmodifiable lists).
• Constructors enforce null-safety (including null-element checks for lists).
• Value semantics provided via equals/hashCode (manual hash implementations).

This would support initialization of the Policy pipeline for examples like the following json or yaml

{
  "sources": [
    {
      "kind": "opamp",
      "format": "jsonkeyvalue",
      "location": "vendor-specific",
      "mappings": [
        { "sourceKey": "sampling_rate", "policyType": "trace_sampling_rate_policy" },
        { "sourceKey": "send_logs", "policyType": "log_export_enabled_policy" }
      ]
    },
    {
      "kind": "file",
      "format": "keyvalue",
      "location": "/some/path/conf.file",
      "mappings": [
        { "sourceKey": "send_metrics", "policyType": "metric_export_enabled_policy" }
      ]
    }
  ]
}

sources:
  - kind: opamp
    format: jsonkeyvalue
    location: vendor-specific
    mappings:
      - sourceKey: sampling_rate
        policyType: trace_sampling_rate_policy
      - sourceKey: send_logs
        policyType: log_export_enabled_policy

  - kind: file
    format: keyvalue
    location: /some/path/conf.file
    mappings:
      - sourceKey: send_metrics
        policyType: metric_export_enabled_policy

Existing Issue(s):

#2546

Testing:

Not needed yet these are just record classes

Documentation:

not needed yet, will be added when specific format parsing is added (eg the above json and/or yaml examples)

Outstanding items:

The functionality to parse json and/or yaml files and create the policy pipeline based on that. Note that the yaml example is exactly what could go into declarative config under a policy pipeline node, so this would naturally migrate to declarative config when it the policy structure is stable and accepted

[Copilot]

Pull request overview

Adds immutable configuration model classes under dynamic-control to represent initial policy source setup (sources + per-source key→policy mappings). This supports upcoming parsing/initialization work for the dynamic Telemetry Policy pipeline.

Changes:

• Introduce PolicyInitConfig as a top-level container for configured policy sources.
• Introduce PolicySourceConfig for per-source configuration (kind/format/location + mappings) with defensive copies and null-element checks.
• Introduce PolicySourceMappingConfig for individual source-key to policy-type mappings with value semantics.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
dynamic-control/src/main/java/io/opentelemetry/contrib/dynamic/policy/registry/PolicyInitConfig.java	Adds immutable top-level init config holding a list of PolicySourceConfig.
dynamic-control/src/main/java/io/opentelemetry/contrib/dynamic/policy/registry/PolicySourceConfig.java	Adds immutable per-source config (kind/format/location + mappings) with defensive list handling and equals/hashCode.
dynamic-control/src/main/java/io/opentelemetry/contrib/dynamic/policy/registry/PolicySourceMappingConfig.java	Adds immutable mapping element (sourceKey → policyType) with equals/hashCode.