feat(P02): opencode integration layer (#2)

18 CI agents, 11 workflows, 11 commands, 5 references, 3 contexts. Zero learnship dependencies.

opencode/command/ci-rollback.md

@@ -0,0 +1,26 @@
+---
+description: Rollback CI phase — revert the last phase or specified phase by resetting to its pre-phase state
+argument-hint: "[phase_number]"
+tools:
+  read: true
+  bash: true
+  write: true
+  edit: true
+  glob: true
+  grep: true
+  task: true
+  question: true
+---
+
+<execution_context>
+@/home/jchery/.config/opencode/ci/workflows/rollback.md
+</execution_context>
+
+<context>
+Arguments: $ARGUMENTS
+</context>
+
+<process>
+Execute the CI rollback workflow end-to-end.
+Preserve all workflow gates, validations, checkpoints, and routing.
+</process>