release: v4.0.0-alpha.2; release.yml keeps the image's Isabelle [skip ci]

v4.0.0-alpha.1's release run (196) was killed in the proofs: release.yml's
full `make init` fetched Isabelle into the workspace and pointed isabelle
at it, without the image's prebuilt HOL-Library, so the proofs built it
from scratch. Nothing was published. Ruled: the tag stays; release.yml runs
`init INIT_PROOFS=0`; LITHOS_VERSION 4.0.0-alpha.2, the first published
alpha. FABRIC-3.md XLVII.5, CHANGELOG.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GE3SDvQn5EoxdGufk84zz2

docs/fabric/FABRIC-3.md

@@ -6165,3 +6165,16 @@ Isabelle2025-2 (HOL-Library and its build database) is a package in this reposit
 `bb247846...e999cb339e`), and the image fetches it into Isabelle's system heaps, checksum pinned,
 its token a Docker build secret. Shown portable first: a fresh Isabelle home holding only that heap
 checks the StarForth session without rebuilding HOL-Library (24 s).
+
+### 5. v4.0.0-alpha.1 not published; v4.0.0-alpha.2
+
+PR #127 merged (`4f675c8b`, acceptance run 192 with the capsules signed); `runner-image.yml` built
+`lithosananke-runner:4f675c8b75b2` with HOL-Library fetched (checksum OK, 4.8 s); PR #128 moved the
+workflows onto it (`233025da`, acceptance run 195 in the new image). `v4.0.0-alpha.1` was tagged on
+`233025da`. Its release run (196) passed acceptance in full, then the proofs step built HOL-Library
+from scratch and was killed (exit 137): `release.yml` ran a full `make init` for the documents'
+packages, which also fetched Isabelle into the workspace and pointed `/usr/local/bin/isabelle` at it
+-- an Isabelle without the image's HOL-Library. Nothing was published. Ruled (Captain Bob,
+2026-11-07): the tag stays where it is; `release.yml` runs `init INIT_PROOFS=0` (as
+`nightly-docs.yml` does), `LITHOS_VERSION` becomes `4.0.0-alpha.2`, and `v4.0.0-alpha.2` is the
+first published alpha.