[Epic] Bundle flags dogfood test (v2.52.0 verification)

[kiki830621]

Purpose

Dogfood verification for v2.52.0 bundle flags (#21).

This is a test epic created via Step 3.B handler simulation. Children below
demonstrate --parent <N> task list edit + --blocked-by <M> three-layer
fallback chain.

Will be closed after verification scenarios pass.

Children

• [Bundle test] Step 1: build schema #23
• [Bundle test] Step 2: add API #24 (blocked by [Bundle test] Step 1: build schema #23)
• [Bundle test] Step 3: add UI #25 (blocked by [Bundle test] Step 2: add API #24)

[kiki830621]

Closing dogfood test issue.

Bundle flag verification (#21 v2.52.0 apply phase) covered:

• 5.1 Epic [Epic] Bundle flags dogfood test (v2.52.0 verification) #22 + 3 children [Bundle test] Step 1: build schema #23-[Bundle test] Step 3: add UI #25 created with task list + Blocked-by chain ✓
• 5.2 GitHub renders task list - [ ] #N as sub-issues with progress bar ✓
• 5.3 GraphQL Layer 1 mutation failed → Layer 2 body blockquote > Blocked by #M persisted (graceful degradation verified) ✓
• 5.4 Idempotency:scan #N references shows exactly 1 entry per child, re-PATCH would no-op ✓
• 5.5 Cross-repo refuse:404 detection on gh issue view proves gate logic ✓

See #21 closing summary for full apply audit trail.