FABRIC-3.md: open new living document (bare metal boot); close FABRIC-2.md

FABRIC-2.md closed/archival as of 2026-09-04 -- its full punch list
(§I) was worked through to completion this session. FABRIC-3.md opens
as the new living document, topic: bare metal boot (FABRIC-2.md §I.6's
own Milestone 8, the one item that couldn't close from a coding
session -- needs a real machine and a human present).

First task written up before executing, per this series' own standing
discipline: merge v2.0.1 into master and verify build/function
equivalence on a clean master tree. Investigated the branch topology
first -- master is a strict ancestor of v2.0.1 (47 commits behind, no
divergent history), so this is a pure fast-forward, not a real merge.

Updated FABRIC-4.md's and .claude/CLAUDE.md's stale pointers at
FABRIC-2.md as "current/living" to point at FABRIC-3.md instead.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019YcT3H2PQeyujrzjqS3Var

FABRIC-4.md

@@ -1,13 +1,14 @@
 # FABRIC-4.md — forward-looking design notes
 
-**Status:** Not a successor to `FABRIC-2.md` and not a punch-list document. `FABRIC-2.md` is
-still the living document — nothing here supersedes it, and this file doesn't follow the
-close-and-carry-forward discipline `FABRIC-0.md` → `FABRIC-1.md` → `FABRIC-2.md` used (that
-chain triggers on *closing* a document; `FABRIC-2.md` isn't closed). This is a separate,
-lower-discipline scratchpad for design ideas caught early — theory-stage, pre-punch-list,
-often missing a stated "why" on purpose (captured as raised, not fully justified yet). An idea
-graduates out of here into `FABRIC-2.md` §I (or wherever `FABRIC-2.md` is by then) once it has
-a real scope, not before.
+**Status:** Not a successor to `FABRIC-3.md` and not a punch-list document. `FABRIC-3.md` is
+the current living document (bare metal boot, opened 2026-09-04, successor to the now-closed
+`FABRIC-2.md`) — nothing here supersedes it, and this file doesn't follow the
+close-and-carry-forward discipline `FABRIC-0.md` → `FABRIC-1.md` → `FABRIC-2.md` → `FABRIC-3.md`
+used (that chain triggers on *closing* a document; `FABRIC-3.md` isn't closed). This is a
+separate, lower-discipline scratchpad for design ideas caught early — theory-stage,
+pre-punch-list, often missing a stated "why" on purpose (captured as raised, not fully
+justified yet). An idea graduates out of here into `FABRIC-3.md` (or wherever the living
+document is by then) once it has a real scope, not before.
 
 ---