feat(build): add full TCR workflow command

Author: apiad

.opencode/commands/build.md

@@ -1,6 +1,33 @@
 ---
-description: TCR (Test-Commit-Revert) workflow for implementing tasks with test-driven development.
+description: Full TCR workflow for implementing plans with test-driven development
 agent: build
 ---
 
-Invoke the `build` agent to manage the project roadmap and implement tasks via a strict, agent-delegated TCR loop.
+Autonomous TCR workflow for implementing tasks from a plan.
+
+### Preconditions
+- Requires a plan (linked to task via `task.planPath` OR passed as argument)
+- If no plan exists → stop and instruct: "Use /plan first to create a plan"
+
+### Workflow
+
+1. **Branch Setup**:
+   - Generate branch name: `feature/<task-id>-<slug>` (e.g., `feature/G.1-implement-auth`)
+   - Create and switch to branch: `git checkout -b <branch-name>`
+
+2. **Step Execution** (for each step in plan):
+   - Invoke `builder` subagent with the step details
+   - Builder does: write test → implement → verify
+   - If builder succeeds → commit step with "Step N: <description>"
+   - If builder fails once → builder retries one fix
+   - If builder fails again → ASK USER for guidance
+
+3. **Completion**:
+   - Merge branch to main
+   - Run final `make test`
+   - Archive task via `task archive --task-id X.X`
+   - Report success summary
+
+### Reporting
+- Report progress after each step
+- Only interrupt for user input on builder failure after retry