feat: merge TODO.md + TODOS.md into unified backlog with shared format reference

Merge TODO.md (roadmap) and TODOS.md (near-term) into one file organized by
skill/component with P0-P4 priority ordering and Completed section. Add shared
review/TODOS-format.md for canonical format. Add static validation tests.

review/TODOS-format.md

@@ -0,0 +1,62 @@
+# TODOS.md Format Reference
+
+Shared reference for the canonical TODOS.md format. Referenced by `/ship` (Step 5.5) and `/plan-ceo-review` (TODOS.md updates section) to ensure consistent TODO item structure.
+
+---
+
+## File Structure
+
+```markdown
+# TODOS
+
+## <Skill/Component>     ← e.g., ## Browse, ## Ship, ## Review, ## Infrastructure
+<items sorted P0 first, then P1, P2, P3, P4>
+
+## Completed
+<finished items with completion annotation>
+```
+
+**Sections:** Organize by skill or component (`## Browse`, `## Ship`, `## Review`, `## QA`, `## Retro`, `## Infrastructure`). Within each section, sort items by priority (P0 at top).
+
+---
+
+## TODO Item Format
+
+Each item is an H3 under its section:
+
+```markdown
+### <Title>
+
+**What:** One-line description of the work.
+
+**Why:** The concrete problem it solves or value it unlocks.
+
+**Context:** Enough detail that someone picking this up in 3 months understands the motivation, the current state, and where to start.
+
+**Effort:** S / M / L / XL
+**Priority:** P0 / P1 / P2 / P3 / P4
+**Depends on:** <prerequisites, or "None">
+```
+
+**Required fields:** What, Why, Context, Effort, Priority
+**Optional fields:** Depends on, Blocked by
+
+---
+
+## Priority Definitions
+
+- **P0** — Blocking: must be done before next release
+- **P1** — Critical: should be done this cycle
+- **P2** — Important: do when P0/P1 are clear
+- **P3** — Nice-to-have: revisit after adoption/usage data
+- **P4** — Someday: good idea, no urgency
+
+---
+
+## Completed Item Format
+
+When an item is completed, move it to the `## Completed` section preserving its original content and appending:
+
+```markdown
+**Completed:** vX.Y.Z (YYYY-MM-DD)
+```