feat(templates): 6-tier escalation ladder — add MiniMax + Fable tiers

New tiers in the coding queue:
  airouter(0-2) → minimax(3-5) → sonnet(6-7) → opus(8-9) → fable(10) → blocked(11+)

- models/claude-fable-5.yaml: Fable 5 model definition (Anthropic cloud, claude runner)
- harnesses/composites/code-fable-tdd-repo/v1: Fable TDD composite (mirrors opus, anthropic-cloud-paul-oauth auth)
- model-registry/harness-roles.yaml: claude-fable-5 → code-fable-tdd-repo under code-tdd role
- model-registry/tiers.yaml: claude-fable-5 added to coding.qualifies_today
- task-templates/workflow/minimax-impl-ready@1.yaml: MiniMax TDD workflow (scope: 3 files / 200 lines / 30m)
- task-templates/workflow/fable-impl-ready@1.yaml: Fable TDD workflow (scope: 5 files / 400 lines / 60m)

Claude-Session: https://claude.ai/code/session_015sCpoFee3LsLKbHQ4FRRWY

models/claude-fable-5.yaml

@@ -0,0 +1,15 @@
+name: claude-fable-5
+provider: anthropic
+endpoint:
+  type: cloud_api
+  api_key_env: ANTHROPIC_API_KEY
+runner: claude
+default_flags:
+  model: "claude-fable-5"
+scores:
+  complexity: 10
+  creativity: 10
+  context_utilisation: 10
+  spec_adherence: 10
+  test_pass_rate: 10
+cost_per_1k_tokens: 0.05