docs(lite): archive superseded lite design/planning docs out of git tracking

Consolidate the lite-wallet documentation down to the single active plan
(lite-wallet-implementation-plan-v2-2026-06-04.md). The 8 prior design/planning
docs — the superseded v1 plan, its runtime-promotion-matrix, the two phase2
runtime-bridge plans, and the four backend artifact/signing design docs — are
moved to docs/_archive/ (added to .gitignore), preserving them locally as
reference while decluttering the tracked tree.

The v2 plan's References section is rewritten to be self-contained: it points to
docs/_archive/ for the historical design docs and to the actual shipping
mechanisms (scripts/build-lite-backend-artifact.sh, lite_backend_artifact_*,
lite_bridge_runtime.cpp) so there are no dangling tracked links. No code,
CMake, or scripts referenced these docs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/lite-wallet-implementation-plan-v2-2026-06-04.md

@@ -1,6 +1,6 @@
 # Lite Wallet Implementation Plan v2 — 2026-06-04
 
-**Status:** Active. **Supersedes** `docs/full-lite-wallet-implementation-plan-2026-05-18.md` (archived).
+**Status:** Active. Supersedes the v1 plan (archived locally under `docs/_archive/`, untracked).
 
 ## Implementation status — end of 2026-06-05 session
 
@@ -181,7 +181,7 @@ Crash/recovery of the wallet *file* (the `.dat`/`.dat.bak` rotation) is already
 - Further investment in `lite_bridge_runtime` dry-dispatch as an execution path.
 - "Readiness ceiling" / "Batch N" framing. Progress is measured by demoable capabilities, not batches.
 
-We retain v1's ground rules, dependency ordering, and the artifact/ABI/signing reference docs (`lite-wallet-backend-artifact-link-contract`, `-production`, `-signing-policy`, `-source-signature-plan`).
+We retain v1's ground rules and dependency ordering; the artifact/ABI/signing design docs are kept in `docs/_archive/` (untracked) for reference.
 
 ## Verification
 
@@ -191,6 +191,9 @@ We retain v1's ground rules, dependency ordering, and the artifact/ABI/signing r
 
 ## References
 
-- v1 (superseded/archived): `docs/full-lite-wallet-implementation-plan-2026-05-18.md`
-- ABI / artifact / signing: `docs/lite-wallet-backend-artifact-link-contract-2026-05-18.md`, `docs/lite-wallet-backend-artifact-production-2026-05-18.md`, `docs/lite-wallet-backend-signing-policy-2026-05-22.md`, `docs/lite-wallet-backend-source-signature-plan-2026-05-20.md`
-- Deferred runtime dynamic-loader design (only if M5 needs it): `docs/lite-wallet-phase2-runtime-bridge-dynamic-loader-sublane-plan-2026-05-23.md`, `docs/lite-wallet-phase2-runtime-bridge-loading-symbol-resolution-plan-2026-05-22.md`
+This plan is the single tracked lite-wallet doc. The prior design/planning docs were moved out of
+version control to **`docs/_archive/`** (git-ignored, kept locally) on 2026-06-05 to declutter the
+tracked tree; consult them there if needed:
+- v1 (superseded): `full-lite-wallet-implementation-plan-2026-05-18.md` + its `lite-wallet-runtime-promotion-matrix-2026-05-18.md`
+- ABI / artifact / signing design: `lite-wallet-backend-artifact-link-contract-2026-05-18.md`, `-artifact-production-2026-05-18.md`, `-signing-policy-2026-05-22.md`, `-source-signature-plan-2026-05-20.md` — the shipping mechanism is `scripts/build-lite-backend-artifact.sh` + `src/wallet/lite_backend_artifact_{contract,resolver}.cpp`; CI signing (M5b) follows the signing-policy/source-signature notes
+- Deferred runtime dynamic-loader design (only if M5 needs it): `lite-wallet-phase2-runtime-bridge-dynamic-loader-sublane-plan-2026-05-23.md`, `-loading-symbol-resolution-plan-2026-05-22.md` (the imported-link lane is implemented in `src/wallet/lite_bridge_runtime.cpp`)