Fix plan branch push/merge reliability in execute-phase

[LeVarez]

Parent: #54

Problem

During v1.1 phase 01 execution, plan branches 01-01, 01-02, 01-03 were never pushed to origin and never merged into the phase branch. Only 01-04 was pushed (because it was the last branch HEAD was on).

Root Cause

The per-plan push/merge loop (lines 395-448 of execute-phase.md) runs as a batch after ALL executors in a wave complete. If execution is interrupted (context limit, checkpoint, etc.), no plan branches get pushed or merged. The final push at step 10.5 (git push origin HEAD) only pushes whichever branch HEAD is currently on.

Evidence

origin/feature/v1.1-01-01  → a69ce5a (base, never updated)
origin/feature/v1.1-01-02  → a69ce5a (base, never updated)
origin/feature/v1.1-01-03  → a69ce5a (base, never updated)
origin/feature/v1.1-01-04  → 3cf67e6 (has work, pushed via git push origin HEAD)

local feature/v1.1-01-01   → bf219b2 (5 commits ahead)
local feature/v1.1-01-02   → f49c010 (7 commits ahead)
local feature/v1.1-01-03   → 6ba3539 (10 commits ahead)

Phase branch: still at 129ae08 (executor work never merged)

Changes (execute-phase.md)

2D. Fix 1 — Push each plan branch IMMEDIATELY after its executor completes

Move push from batch loop to right after each executor returns:

cd "$WORK_DIR" && git push origin "$PLAN_BRANCH" 2>/dev/null || git push -u origin "$PLAN_BRANCH" 2>/dev/null || true

2D. Fix 2 — Push ALL plan branches at step 10.5

Replace git push origin HEAD with a loop that pushes all known plan branches plus the phase branch.

2D. Fix 3 — Add push to offer_next routes

Even partial completions push to origin.

2E. Make merge loop resilient

After each wave's executors complete AND branches are pushed, merge into phase branch with explicit error handling. If merge fails → STOP (don't silently continue with a phase branch missing executor work).

cd "$WORK_DIR" && git checkout "$DESIGNATED_BRANCH"
for each completed plan branch:
  MERGE_RESULT=$(git merge "$PLAN_BRANCH" --no-ff -m "merge: plan into phase" 2>&1)
  if echo "$MERGE_RESULT" | grep -q "CONFLICT\|fatal"; then
    # STOP — don't proceed with broken state
  fi
done
git push origin "$DESIGNATED_BRANCH" || true

Files

• .claude/commands/vit/execute-phase.md (zones 2D, 2E)
• .claude/vit/workflows/execute-phase.md (push_to_remote step)

[LeVarez]

Critical implementation note

The merge loop fix (#2E) is the highest priority item — it's the root cause that cascades into #57 (verification "never complete") and partially into #59 (gap closure). Without reliable merges, the phase branch never receives executor work.

Dependency chain:

#56 (push/merge) ─┬─► #57 (verification sees work)
                   └─► #58 (phase has content to merge into milestone)
                        └─► #58 rebase (other branches get merged content)

Key detail: linear chain behavior

The current per-plan branch mode runs executors sequentially in one worktree, creating a linear commit chain (01-01 → 01-02 → 01-03 → 01-04). Each plan branch is a superset of all previous plans. This means:

• Merging plan branches into the phase branch is a series of fast-forwards
• The last plan branch contains ALL work
• If only the last branch is merged, all work reaches the phase branch

This is an acceptable architecture for now — the push/merge reliability fix is what matters, not reworking parallel execution.