sdk: bootstrap standalone repo (P0)

- Dual license (LICENSE / LICENSE-MIT / LICENSE-APACHE) matching the crate manifests.
- ADRs 0001-0005: kernel base (direct 5.10->6.18.46 forward-port), tiered MC/DC,
  standalone repo, CI runner (3rd repo-scoped runner on 0640), driver source-of-truth.
- README goal 1 reconciled to the verified 6.18.46 forward-port (was stale plan44/6.6).
- Drop tracked build objects (*.o now gitignored).
- Capture the display (VOP dclk-pol + WIN1) and GT911 touch bring-up VERIFIED docs
  + capabilities-audit update from this session.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017wB8KB3MMQztRDXCMCkPrf

docs/decisions/0002-mcdc-tiering.md

@@ -0,0 +1,28 @@
+# ADR 0002 — Tiered MC/DC coverage policy
+
+**Status:** Accepted (2026-08-25).
+
+## Context
+The goal "port + harden 100% of drivers to 100% MC/DC" is infeasible as literally
+stated: ~97% of driver LOC is vendor blobs (the AIC8800 wifi driver alone is 88.5K
+lines) that we cannot meaningfully unit-test to MC/DC on the host. Forcing MC/DC on
+that code would be theatre, not assurance.
+
+## Decision
+A **two-tier** policy, measured against the Hardware Abstraction Seam:
+
+- **Tier 1 — our own hardware-facing code → real 100% MC/DC.** `modbus_engine.c`,
+  `relays.c`, `warden_rga.c` (wrapper), `hpmcu.rs`, `devmem.rs`, `freshness.c`, plus
+  the two smallest near-mainline drivers where feasible. Enforced in CI
+  (`gcc-14 -fcondition-coverage` + `gcov-14 --conditions`; `cargo-llvm-cov --mcdc`
+  for Rust).
+- **Tier 2 — ported/vendor drivers → fault-injection + branch coverage + benchmarks**
+  against the simulator, behind a stable seam. Explicitly NOT literal MC/DC.
+
+## Consequences
+- Matches the user's framing: "as many drivers as possible at 100% MC/DC; for the
+  rest, a very serious testing and benchmarking system."
+- The seam is the shared object: the same thing MC/DC is measured against and the
+  simulator implements — the two goals reinforce, not duplicate.
+- Every Tier-1 file gets a `drivers/<name>-mcdc/` host harness with an
+  `enforce-mcdc.sh` that fails CI below 100%.