Revert "feat(ecc): prune plugin 43→12 items, promote 7 rules to .claude/rules/ (#245)"

This reverts commit 1bd68ff534.

.opencode/commands/checkpoint.md

@@ -0,0 +1,67 @@
+---
+description: Save verification state and progress checkpoint
+agent: build
+---
+
+# Checkpoint Command
+
+Save current verification state and create progress checkpoint: $ARGUMENTS
+
+## Your Task
+
+Create a snapshot of current progress including:
+
+1. **Tests status** - Which tests pass/fail
+2. **Coverage** - Current coverage metrics
+3. **Build status** - Build succeeds or errors
+4. **Code changes** - Summary of modifications
+5. **Next steps** - What remains to be done
+
+## Checkpoint Format
+
+### Checkpoint: [Timestamp]
+
+**Tests**
+- Total: X
+- Passing: Y
+- Failing: Z
+- Coverage: XX%
+
+**Build**
+- Status: ✅ Passing / ❌ Failing
+- Errors: [if any]
+
+**Changes Since Last Checkpoint**
+```
+git diff --stat [last-checkpoint-commit]
+```
+
+**Completed Tasks**
+- [x] Task 1
+- [x] Task 2
+- [ ] Task 3 (in progress)
+
+**Blocking Issues**
+- [Issue description]
+
+**Next Steps**
+1. Step 1
+2. Step 2
+
+## Usage with Verification Loop
+
+Checkpoints integrate with the verification loop:
+
+```
+/plan → implement → /checkpoint → /verify → /checkpoint → implement → ...
+```
+
+Use checkpoints to:
+- Save state before risky changes
+- Track progress through phases
+- Enable rollback if needed
+- Document verification points
+
+---
+
+**TIP**: Create checkpoints at natural breakpoints: after each phase, before major refactoring, after fixing critical bugs.