docs: v2 (GitHub-backed) design doc

MEMORY.md

@@ -8,10 +8,19 @@
 
 ## Now / next (the resume point)
 
-- **Nothing is in flight.** `main` is the complete state; no open PRs; the only
-  branch is `main`. v1.4.1 (docs-only, migration-readiness) is committed on
-  `main` — if no `v1.4.1` tag exists yet, tagging it is pending the owner's
-  confirmation (a tag push triggers the release; see CLAUDE.md → Releasing).
+- **In flight: the v2 design doc**
+  (`docs/superpowers/specs/2026-08-04-v2-github-backend-design.md`, branch
+  `docs/v2-design`). v2 makes every item a GitHub issue (collision-free ids **by
+  construction** — retiring the whole #12/#13/#14 triad), a 4-level
+  release→milestone→feature→task tree, and a **pluggable `Backend` interface**
+  (GitHub is one impl). Settled via a ten-fork brainstorm + an adversarial
+  (Fable) review; open items are flagged in the doc. No v2 *code* yet. v1.4.1 is
+  committed and tagged on `main`.
+- **Strategic direction:** finish the 1.x queue (below) → **freeze 1.x** → build
+  v2 against that doc. The freeze has a HARD prerequisite (see the #14 bullet): a
+  `selfupdate` cross-major guard must ship in the last 1.x release *before* v2
+  lands on `main`, or vendored 1.x copies (`taxjot`/`byteorb`/`stead`)
+  self-update across the major boundary into a different file format.
 - **Next up, if told "continue where we left off": issue #14 — `validate --refs`**,
   a reference-integrity check. Agreed shape (triage comment on the issue): v1 detects
   *dangling* refs only (`@deps=`/`@rel=`/`## <ID>` notes header pointing at an ID
@@ -20,7 +29,11 @@
   in `tasks.py` is already half the engine; short-form IDs (`T-12` ≡ `T-0012`) must
   be handled (see the v1.3.0 LEARNINGS entry). Fold #25 (validate silently ignores
   unknown args) into the same round — that bug becomes dangerous the moment
-  `validate` grows its first flag.
+  `validate` grows its first flag. **Also bundle into this same last-1.x release a
+  `selfupdate` cross-major guard** (refuse cross-major updates, or repoint
+  canonical to a frozen `v1` branch) — HARD prereq before v2 merges to `main`
+  (v2 doc → Sequencing). v2's GitHub-issue ids make the collision triad moot, so
+  #14 is explicitly a *1.x-only* deliverable.
 - Queue after #14 (recommended order, from the issue-triage comments): #16 (CLI verb
   for the `# Milestones` registry), #11's remaining half (`note ID` verb — retitle
   shipped in v1.2.0), #6 (refuse mutating commands on main), #5 (docs: CLI-only vs
@@ -30,7 +43,15 @@
   `@pr`/`@branch` freshness). #13's `reserve N` stays deferred unless a real gap is
   observed (recorded on the issue).
 
-## What just happened (2026-06-21 → 2026-07-15)
+## What just happened (2026-06-21 → 2026-08-04)
+
+**2026-08-04 — v2 planning opened.** A ten-fork brainstorm plus an adversarial
+(Fable) review produced the committed v2 design doc: GitHub issues as a
+pluggable synced backend, identity ⟂ organization, allocate-on-`new` /
+batch-on-`sync`, prose repo-primary (offline-first preserved). No v2 code yet;
+the 1.x queue ships first, then a 1.x freeze. See the doc's Sequencing.
+
+**2026-06-21 → 2026-07-16 — the six-release 1.x run.**
 
 Six releases, each driven by real usage in consumer repos. The *why* behind the
 decisions is in `LEARNINGS.md`; the renumber and id-allocation rounds also have full