chore(config): retire unread keys [dynamic], [evidence], [variants], [models] patcher

Nothing in src reads config.dynamic, config.evidence or config.variants, and
[models] patcher was only echoed into harness.json. They now go through the
existing RETIRED_KEYS mechanism and fail with RetiredConfigError naming why
("retired 2026-10-02 because nothing ever read it: ..."); RETIRED_KEYS now
carries the full reason per key so the HarnessX entries keep their wording.

- DynamicConfig, EvidenceConfig, VariantsConfig and their loaders removed;
  ModelConfig.patcher removed. resolved_config.json loses those sections.
- harness.json keeps its shape: model_roles.patcher is always null.
- RELEASE_NOTES "Unreleased" lists the keys and the output shape change.
- Delete .opencode/skills/openultrasast-kiro-impl: it pointed agents at the
  retired openrouter-sast-harness tasks.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

RELEASE_NOTES.md

@@ -1,5 +1,21 @@
 # Unreleased
 
+## Unread config keys retired (2026-10-02)
+
+These keys loaded but nothing ever read them. They now fail with `RetiredConfigError` (the
+CLI prints it and exits 2), naming why. Remove them from your config:
+
+- `[models] patcher`: no patching stage calls a model.
+- `[dynamic] enabled`, `[dynamic] network_scope`: no dynamic or deep tier exists yet.
+- `[evidence] minimum_report_verified`, `minimum_exploit`, `minimum_patch`: evidence tiers
+  come from the program model's ladder, not from configuration.
+- `[variants] enabled`, `[variants] max_mechanisms`: the variant search they configured was
+  deleted earlier.
+
+**Output shape.** `resolved_config.json` no longer has the `dynamic`, `evidence` and
+`variants` sections or `models.patcher`. `harness.json` keeps its shape:
+`model_roles.patcher` is always `null`, like `model_roles.verifier`.
+
 ## HarnessX removed; the ax plane is the agentic path (2026-09-30)
 
 HarnessX, the optional agentic extra (`openultrasast[harnessx]`), is removed with its code,