docs(plan): settle Phase V forks V1-V4

V1 semver via project(VERSION), ext-state version stamp first-wave.
V2 plain -beta suffix. V3 console line + panel readout. V4 reverses
prior rec: beta ships as a separate coexisting binary with isolated
ext-state namespace + command-id prefix.

PLAN.md

@@ -445,29 +445,33 @@ CONTEXT.md §Prune (Settled forks).
 > Namespaced **`V` (Versioning)** alongside `M`/`D`/`B`/`R` because it is a distinct
 > concern (build identity + channel isolation) that touches CMake, `main.cpp`'s
 > forever-stable command-id contract, and the `"reasampler"` ext-state — not a
-> capture step. Product framing + the full option analysis + open forks:
-> `docs/product/versioning-and-release.md`. **Forks V1–V4 UNSETTLED — awaiting
-> Daniel.** No points are scoped-to-build until Daniel picks; the note lays out the
-> recommendation (semver via `project(VERSION)` + ext-state version stamp; beta =
-> branch-discipline/one-at-a-time built on a compile-time channel flag, with true
-> simultaneous coexistence designed-as-a-seam but deferred). Deploy/CD wiring hands
-> off to dev-ops.
+> capture step. Product framing + the full option analysis: `docs/product/versioning-
+> and-release.md`. **Forks V1–V4 SETTLED (Daniel, 2026-07-26)** — semver via
+> `project(VERSION)` + ext-state version stamp prioritized first-wave; plain `-beta`
+> suffix; console line + panel readout (about-box deferred); and **beta ships as a
+> separate, fully isolated coexisting binary (beta-in-isolation)** — a reversal of the
+> note's original one-at-a-time recommendation. Deploy/CD wiring (now two named
+> artifacts per platform) hands off to dev-ops. Build-scoped points to be drawn up.
 
-## Open forks — for Daniel (see `docs/product/versioning-and-release.md`)
-- **V1 — version scheme.** Recommend semver, single source of truth in CMake
-  `project(reaper_reasampler VERSION x.y.z)`, threaded into the binary; **plus a
-  writing-version stamp in the `"reasampler"` ext-state blob** for forward
-  migration/detection. Approve scheme + whether the ext-state stamp lands first wave.
-- **V2 — beta suffix source.** Recommend `git describe` decorating beta builds while
-  `project(VERSION)` owns the release triple. Approve or simplify to plain `-beta`.
-- **V3 — user-visible home.** Recommend startup console line (`"ReaSampler x.y.z
-  loaded"`) + a bank-panel version/channel readout; about-box deferred. Panel
-  placement is the residual polish call.
-- **V4 — beta channel shape (the big one).** Recommend **branch-discipline /
-  one-installed-at-a-time (Option B) built on a compile-time channel flag (Option
-  C)**, with **true simultaneous coexistence (Option A) seam-designed but deferred**.
-  Sharp edges that must be decided explicitly: the forever-stable command-id prefix
-  (`CEREBELLUM_REASAMPLER_`) must not collide between coexisting builds, and the
-  `"reasampler"` ext-state namespace must not let a beta corrupt a stable project's
-  state — so the **ext-state-across-a-channel-swap policy** (isolate vs.
-  stay-compatible/stamp-and-detect vs. accept-discipline) is genuinely Daniel's call.
+## Settled decisions (Daniel, 2026-07-26 — see `docs/product/versioning-and-release.md`)
+- **V1 — version scheme: APPROVED as recommended.** Semver, single source of truth in
+  CMake `project(reaper_reasampler VERSION x.y.z)`, threaded into the binary. **The
+  `"reasampler"` ext-state writing-version stamp is prioritized to the first wave, not
+  deferred** — every project saved without the stamp is harder to migrate later, so
+  the migration seam lands early.
+- **V2 — beta suffix: plain `-beta`.** `project(VERSION)` owns the release triple; beta
+  carries a `-beta` suffix. `git describe` decoration considered and rejected for
+  legibility.
+- **V3 — user-visible home: recommendation accepted.** Startup console line
+  (`"ReaSampler x.y.z loaded"`) + a bank-panel version/channel readout; about-box
+  deferred. Panel placement is the residual polish call.
+- **V4 — beta channel shape: BETA-IN-ISOLATION (full coexistence).** *Reverses the
+  original recommendation.* Beta ships as a **separate binary** (`reaper_reasampler_
+  beta`) with an **isolated ext-state namespace** (distinct from stable's
+  `"reasampler"` — a beta cannot corrupt a stable project's saved state) and an
+  **isolated forever-stable command-id prefix** (beta/stable keybindings don't
+  collide), so both install and run side-by-side. Built through a compile-time channel
+  flag (`-DREASAMPLER_CHANNEL=beta`) as the mechanism. **Two permanent commitments
+  locked in:** a second forever-stable command-id prefix and a second ext-state
+  namespace. **Dev-ops:** the build now produces two named artifacts (stable + beta)
+  per platform.