feat(providers): map Herdr protocol events (COD-438)

[shivros]

Summary

Implements the pure Herdr protocol-19 mapper for IRIS-12b.

• Converts workspace/tab/pane lifecycle events into ordered deterministic Iris write intents.
• Converts agent-status events into contact, workspace-thread, and system-message intents.
• Preserves canonical event metadata for the ingest/persistence seam; explicitly drops v1-out-of-scope event kinds.
• Supports dotted subscription names and data.type fallback, rejects empty bridge replay IDs, and handles pane_moved embedded workspace lifecycle.

Verification

cargo test -p iris-providers herdr
cargo clippy -p iris-providers --all-targets -- -D warnings
cargo build --all-targets
cargo test --all-targets
cargo fmt --all -- --check
cargo run -p iris-codegen --bin iris-codegen -- check

All passed. imap-proto v0.10.2 retains its pre-existing future-incompatibility warning.

Notes

The mapper deliberately emits typed persistence intents rather than adding storage or HTTP I/O. COD-437 owns that ingest/persistence transaction seam.

[shivros]

🤖 Automated Review Panel

GPT-5.6-terra (openai-codex)

Changes requested; all correctness findings fixed before PR.

• Added canonical handling for dotted protocol-19 subscription event names and the data.type fallback.
• Added explicit v1 drops and table coverage for pane.output_matched / pane.scroll_changed.
• Rejects malformed agent-status events lacking a pane identity and blank bridge replay IDs.
• Retains canonical event payload metadata for the later ingest/persistence seam.

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Gemini 3 Flash (google/gemini-3-flash-preview)

Changes requested; all correctness findings fixed before PR.

• pane_moved now emits embedded created-workspace upsert, closed-workspace archive, and destination workspace metadata intents in deterministic order.
• Dotted event-key compatibility and empty event-ID rejection covered by regression tests.

Post-review validation passed: provider tests (7 Herdr tests), strict clippy, full workspace build/test, fmt, and codegen freshness. The only output was the pre-existing imap-proto v0.10.2 future-incompatibility warning.

[shivros]

Auto-Merge Gate

Confidence: 0.91

The PR clearly implements COD-438's pure, deterministic Herdr protocol-19 mapping layer. The focused mapping suite passes locally (7 tests); CI reports green Test, Format Check, Clippy, Secret Scan, Dependency Audit, and Creed context drift. The diff is limited to the new mapper and its module export; no credentials, deployment, destructive behavior, or manual-review marker was found.

Self-authored PR: this visible rationale is the audit record if GitHub declines formal self-approval.