AMPR-180 #508: Emission protocol foundation (Wave 0)

[wow-miley]

Closes #508 (Linear AMPR-180).

Summary

I introduce the Emission domain object and EmissionEvent family in commonMain, with four core kinds (Prose, Decision, Confirmation, Sensor), the shared Confidence enum migrated through PerceptionEvaluator/OutcomeEvaluator, a content-deterministic dedup key via inputDigest (SHA-256/16 hex) kept separate from random EmissionIds, full EmissionProvenance, and stable @SerialNames. EmissionEvent.{Produced,Resolved} are registered on EventRegistry and categorized in SignificanceAwareEventLogger; the emission and emission-dedup concept cells (plus the _index entry) document the CHI primitive.

Test plan

• `./gradlew :ampere-core:jvmTest` — 33 new tests pass (serialization round-trip per payload variant, bus delivery, registry membership, digest determinism, Confidence parsing)
• `./gradlew :ampere-core:ktlintFormat` clean
• `./gradlew :ampere-core:compileCommonMainKotlinMetadata` passes

🤖 Generated with Claude Code

[github-actions]

Concept staleness check — 2 warning(s).

These changes touched files listed under a concept's tracked_sources without updating the concept file. Either update the concept (and bump last_verified) or include a Concept-Verified: <ConceptName> trailer in a commit on this PR.

Validator output

⚠ Concept 'EventSerialBus' may be stale: ampere-core/src/commonMain/kotlin/link/socket/ampere/agents/events/utils/SignificanceAwareEventLogger.kt matches tracked_sources pattern ampere-core/src/commonMain/kotlin/link/socket/ampere/agents/events/utils/SignificanceAwareEventLogger.kt but docs/concepts/event-serial-bus.md was not modified.
⚠ Concept 'PropelLoop' may be stale: ampere-core/src/commonMain/kotlin/link/socket/ampere/agents/domain/reasoning/Confidence.kt matches tracked_sources pattern ampere-core/src/commonMain/kotlin/link/socket/ampere/agents/domain/reasoning/** but docs/concepts/propel-loop.md was not modified.

validate-concepts: 2 warning(s). Validator informs; never blocks.