Add tdd-gate context, *-code-tdd-repo composites, and TDD task templates

Adds the tdd-gate harness context (TEST_PASS_REQUIRED=true + CLAUDE.md
methodology) and five provider-specific TDD composites that layer
tdd-protect + tdd-gate + python-dev + tdd-file-lock on top of the
existing code-* layer stacks. Matching task templates for sonnet, opus,
haiku, minimax, and airouter. allowed_failing_tests support noted in
warnings pending M19 pre-test hook implementation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

task-templates/haiku-code-tdd.yaml

@@ -0,0 +1,22 @@
+name: haiku-code-tdd
+description: "Haiku code agent with TDD enforcement — tests are read-only and must pass before the task finishes"
+model: haiku
+harness: code-haiku-tdd-repo/v1
+requires_tags: [claude-code, coding-agent, git-access, project-repo, tdd-gate]
+required_params: [repo_url, agent_repo_url]
+defaults:
+  timeout: 1800
+pre_actions:
+  - type: clone
+    repo: "{{ repo_url }}"
+    branch: main
+    depth: 1
+blocked_combinations:
+  - field: on_success
+    contains_type: commit_pr
+    message: "Use agent_repo instead of commit_pr — avoids F77 SSH alias URL bug"
+warnings:
+  - "Test files are locked read-only at the OS level — agent cannot modify them"
+  - "Task will be marked failed if the test suite is not green on completion"
+  - "Haiku is best for narrow, well-scoped TDD tasks — avoid broad refactors"
+  - "allowed_failing_tests support requires M19 (pre-test hook) to be deployed"