feat(routing): add tiers.yaml + rename spec/review-arch templates to airouter

W1 stage-routing work:
- model-registry/tiers.yaml: defines planning/spec-test/coding tier floors
  (complexity≥9/creativity≥9/context≥9 | spec_adherence≥9/test_pass_rate≥9 |
  spec_adherence≥7/test_pass_rate≥7) with qualifies_today lists
- spec-draft-airouter@2.yaml: honest name for what was spec-draft-opus@1
  (always ran Qwen3.6/airouter, not Opus)
- review-spec-arch-airouter@1.yaml: honest name for review-spec-arch-opus@1

Old @1 files kept for in-flight task backward-compatibility.

Claude-Session: https://claude.ai/code/session_01B35bPAKv5uyW1F9gzMcRN7

task-templates/workflow/review-spec-arch-airouter@1.yaml

@@ -0,0 +1,49 @@
+name: review-spec-arch-airouter
+version: 1
+description: Architecture review of a spec draft
+runtime: best-practices-airouter-repo
+input:
+  state: spec-draft
+  tags_forbidden: [security-sensitive]
+  required_artifacts: [spec_file]
+output:
+  state: spec-reviewed-arch
+scope_budget:
+  files_modified_max: 2
+  lines_diff_max: 150
+  wall_clock_seconds_max: 1800
+nodes:
+  - id: agent
+    kind: agent
+    template: best-practices-airouter-repo
+    cli: agentic
+    model: Qwen3.6
+    labels: [airouter]
+    runtime_env:
+      AGENT_REPO_URL: "git@gitea.oreillyit.nz-ai-enablement:skynet/agent-runtimes-agents.git"
+      AGENT_BRANCH: "spec/auto-draft"
+    prompt: |
+      The agent-runtimes project repo is cloned at /workspace/project.
+      Change to that directory before doing any work.
+
+      Review the spec draft for the following concept.
+
+      **Title**: ${item.title}
+
+      **Original concept**:
+      ${item.body}
+
+      Steps:
+      1. cd /workspace/project
+      2. Find the spec file: ls spec/ and look for a file matching the concept title slug
+      3. Read the spec file completely
+      4. Review it against architectural best practices:
+         - Are requirements testable and unambiguous?
+         - Are there security implications not addressed?
+         - Are interfaces and data contracts clearly defined?
+         - Are edge cases and failure modes covered?
+      5. Write your review findings to /workspace/.agent-output/review.md with a PASS or
+         REWORK verdict and specific findings
+      6. Call task_complete with "PASS" or "REWORK: <one-line reason>"
+escalation:
+  contract_ambiguous: review-spec-opus