fix: make subagent context hook load state from correct branch

The hook runs in the parent's context, so runtime worktree detection
and plan loading were reflecting the parent's state, not the subagent's.
Replace with static branch references and a bootstrap section that
instructs subagents to load unit-scoped state after entering their
own worktree.

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

Author: jwaldrip

plugin/hooks/subagent-context.sh

@@ -116,15 +116,6 @@ if [ -f "${INTENT_DIR}/completion-criteria.md" ]; then
   echo ""
 fi
 
-# Current plan is ephemeral state - keep in han keep
-PLAN=$(load_keep_value current-plan.md)
-if [ -n "$PLAN" ]; then
-  echo "### Current Plan"
-  echo ""
-  echo "$PLAN"
-  echo ""
-fi
-
 # Display testing requirements if configured (stored in intent.md frontmatter)
 if [ -f "$INTENT_FILE" ]; then
   TESTING_JSON=$(han parse yaml testing --json < "$INTENT_FILE" 2>/dev/null || echo "")
@@ -238,42 +229,45 @@ echo ""
 echo "## AI-DLC Workflow Rules"
 echo ""
 
-# Get current branch and working directory
-CURRENT_BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
-CURRENT_DIR=$(pwd)
-IS_WORKTREE=$(git rev-parse --is-inside-work-tree 2>/dev/null && [ -f "$(git rev-parse --git-dir)/commondir" ] && echo "yes" || echo "no")
+# Branch references for cross-branch state access
+echo "### Branch References"
+echo ""
+echo "- **Intent branch:** \`ai-dlc/${INTENT_SLUG}/main\`"
+echo "- **Intent worktree:** \`/tmp/ai-dlc-${INTENT_SLUG}/\`"
+echo ""
+echo "To access intent-level state from a unit branch:"
+echo "\`\`\`bash"
+echo "han keep load --branch \"ai-dlc/${INTENT_SLUG}/main\" <key>"
+echo "\`\`\`"
+echo ""
 
-echo "### Current Working Context"
+echo "### Bootstrap (MANDATORY)"
 echo ""
-echo "- **Branch:** \`${CURRENT_BRANCH}\`"
-echo "- **Directory:** \`${CURRENT_DIR}\`"
-if [ "$IS_WORKTREE" = "yes" ]; then
-  echo "- **Worktree:** ✅ Yes (isolated workspace)"
-else
-  echo "- **Worktree:** ⚠️ NO - You should be in a worktree!"
-fi
+echo "Your spawn prompt tells you which worktree and branch to use."
+echo "After entering your unit worktree, load unit-scoped state:"
+echo ""
+echo "\`\`\`bash"
+echo "# Load previous context from your unit branch"
+echo "han keep load current-plan.md --quiet 2>/dev/null || true"
+echo "han keep load scratchpad.md --quiet 2>/dev/null || true"
+echo "han keep load blockers.md --quiet 2>/dev/null || true"
+echo "han keep load next-prompt.md --quiet 2>/dev/null || true"
+echo "\`\`\`"
+echo ""
+echo "These are scoped to YOUR branch. Read them to understand prior work on this unit."
 echo ""
 
-echo "### Worktree Isolation (MANDATORY)"
+echo "### Worktree Isolation"
 echo ""
-echo "All bolt work MUST happen in an isolated worktree at:"
-echo "\`/tmp/ai-dlc-{intent-slug}-{unit-slug}/\`"
+echo "All bolt work MUST happen in an isolated worktree."
+echo "Working outside a worktree will cause conflicts with the parent session."
 echo ""
-if [ "$IS_WORKTREE" = "yes" ] && [[ "$CURRENT_BRANCH" == ai-dlc/* ]]; then
-  echo "✅ You are in the correct worktree on an AI-DLC branch. Continue working here."
-elif [[ "$CURRENT_DIR" == /tmp/ai-dlc-* ]]; then
-  echo "✅ You are in an AI-DLC worktree directory. Continue working here."
-else
-  echo "🛑 **STOP!** You are NOT in a worktree!"
-  echo ""
-  echo "Before doing ANY work, you must:"
-  echo "1. Have the parent create the worktree"
-  echo "2. cd to the worktree directory"
-  echo "3. Verify you're on the unit branch"
-  echo ""
-  echo "Working outside a worktree will cause conflicts with the parent session."
-fi
+echo "After entering your worktree, verify:"
+echo "1. You are in \`/tmp/ai-dlc-${INTENT_SLUG}-{unit-slug}/\`"
+echo "2. You are on the correct unit branch (\`git branch --show-current\`)"
+echo "3. You loaded unit-scoped state (see Bootstrap above)"
 echo ""
+
 echo "### Before Stopping"
 echo ""
 echo "1. **Commit changes**: \`git add -A && git commit\`"