fix(ai-review): address all review findings — restore allowedTools, add fallbacks

Fixes from ai-review bot feedback on PR #838:

- [HIGH] Restore --allowedTools with Agent added (was incorrectly removed,
  not redundant with bypassPermissions — it's a tool whitelist)
- [MED] Add inline fallback prompts when subagent files missing from base branch
- [MED] Add graceful degradation in orchestrator for Agent tool failures
  and empty subagent prompts
- [MED] Replace hardcoded PROMPT_EOF delimiters with random openssl-generated
  delimiters to prevent early heredoc termination
- [LOW] Add per-subagent turn budget guidance (8-10 turns each, 50 total)
- [LOW] Add "Do NOT fetch diff separately" instruction to all 4 subagent prompts

.github/workflows/ai-review.yml

@@ -219,25 +219,48 @@ jobs:
 
           # Load subagent prompts (all from base branch for security)
           SECURITY_PROMPT=$(git show "origin/${BASE_REF}:.github/review-prompts/security.md" 2>/dev/null || echo "")
+          if [ -z "$SECURITY_PROMPT" ]; then
+            echo "::warning::security.md not found on base branch — using inline fallback"
+            SECURITY_PROMPT="You are a security reviewer. Check the diff for injection vulnerabilities, auth bypasses, race conditions, secrets exposure, and supply chain risks. Report findings as: #### [HIGH|MEDIUM|LOW] [SECURITY] file:line"
+          fi
+
           QUALITY_PROMPT=$(git show "origin/${BASE_REF}:.github/review-prompts/quality.md" 2>/dev/null || echo "")
+          if [ -z "$QUALITY_PROMPT" ]; then
+            echo "::warning::quality.md not found on base branch — using inline fallback"
+            QUALITY_PROMPT="You are a code quality reviewer. Check for error handling gaps, false assumptions, performance issues, dead code, and test gaps. Report findings as: #### [HIGH|MEDIUM|LOW] [QUALITY] file:line"
+          fi
+
           CCS_PROMPT=$(git show "origin/${BASE_REF}:.github/review-prompts/ccs-compliance.md" 2>/dev/null || echo "")
+          if [ -z "$CCS_PROMPT" ]; then
+            echo "::warning::ccs-compliance.md not found on base branch — using inline fallback"
+            CCS_PROMPT="You are a CCS compliance reviewer. Check for: no emojis in CLI output, getCcsDir() usage, cross-platform parity, --help updates, string-only settings, conventional commits. Report findings as: #### [HIGH|MEDIUM|LOW] [CCS] file:line"
+          fi
+
           ADVERSARIAL_PROMPT=$(git show "origin/${BASE_REF}:.github/review-prompts/adversarial.md" 2>/dev/null || echo "")
+          if [ -z "$ADVERSARIAL_PROMPT" ]; then
+            echo "::warning::adversarial.md not found on base branch — using inline fallback"
+            ADVERSARIAL_PROMPT="You are an adversarial reviewer. Find what prior reviewers missed: interaction bugs, implicit coupling, missing rollback, boundary violations. Do NOT repeat prior findings. Report as: #### [HIGH|MEDIUM|LOW] [ADVERSARIAL] file:line"
+          fi
 
-          echo "security_prompt<<PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          SECURITY_DELIM="SECURITY_$(openssl rand -hex 16)"
+          echo "security_prompt<<${SECURITY_DELIM}" >> "$GITHUB_OUTPUT"
           echo "$SECURITY_PROMPT" >> "$GITHUB_OUTPUT"
-          echo "PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          echo "${SECURITY_DELIM}" >> "$GITHUB_OUTPUT"
 
-          echo "quality_prompt<<PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          QUALITY_DELIM="QUALITY_$(openssl rand -hex 16)"
+          echo "quality_prompt<<${QUALITY_DELIM}" >> "$GITHUB_OUTPUT"
           echo "$QUALITY_PROMPT" >> "$GITHUB_OUTPUT"
-          echo "PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          echo "${QUALITY_DELIM}" >> "$GITHUB_OUTPUT"
 
-          echo "ccs_prompt<<PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          CCS_DELIM="CCS_$(openssl rand -hex 16)"
+          echo "ccs_prompt<<${CCS_DELIM}" >> "$GITHUB_OUTPUT"
           echo "$CCS_PROMPT" >> "$GITHUB_OUTPUT"
-          echo "PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          echo "${CCS_DELIM}" >> "$GITHUB_OUTPUT"
 
-          echo "adversarial_prompt<<PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          ADVERSARIAL_DELIM="ADVERSARIAL_$(openssl rand -hex 16)"
+          echo "adversarial_prompt<<${ADVERSARIAL_DELIM}" >> "$GITHUB_OUTPUT"
           echo "$ADVERSARIAL_PROMPT" >> "$GITHUB_OUTPUT"
-          echo "PROMPT_EOF" >> "$GITHUB_OUTPUT"
+          echo "${ADVERSARIAL_DELIM}" >> "$GITHUB_OUTPUT"
 
       - name: Run Claude Code Review
         id: claude-review
@@ -300,6 +323,7 @@ jobs:
             --model ${{ env.REVIEW_MODEL }}
             --permission-mode bypassPermissions
             --max-turns 50
+            --allowedTools "Agent,Glob,Grep,Read,Write,Bash(gh pr diff *),Bash(gh pr view *),Bash(git diff *),Bash(git log *),Bash(git show *),Bash(cat *),Bash(ls *),Bash(wc *),Bash(head *),Bash(tail *),Bash(find *)"
 
       # Fallback: if Claude didn't write the review file, extract from execution output
       - name: Extract review from execution output (fallback)