reconcile: carry FHE+attestation mutex-fix analysis onto refactored main

WIP main was an orphaned old base; remote main is the canonical refactor
(p3q/+starkfri/ split, slot 0x012205=P3Q, newer dep pins) and already
contains the P3Q work. The only genuinely-new, non-superseded WIP artifact
is this still-relevant data-race analysis (remote fhe/*.go still has no
mutex). dex/engine_embedded.go intentionally dropped: remote refactor
removed the embedded AMM in favor of the inert default and added
inert_no_embedded_test.go asserting it is gone.

Full WIP preserved on branch wip/local + tag backup/pre-reconcile-main.

FHE_MUTEX_FIX_PLAN.md

@@ -0,0 +1,102 @@
+# FHE + Attestation Mutex Fix Plan
+
+**Status**: Analysis complete (agent a0677f0c, 2026-04-10). Implementation blocked by usage limit.
+
+## Threat Model
+
+- **Assets**: Consensus determinism across validator nodes
+- **Adversary**: Concurrent EVM transaction execution within a block
+- **Attack**: Unprotected map writes → data races → non-determinism → chain split
+
+## Findings
+
+### REAL bugs requiring fix
+
+1. **FHE** — `/Users/z/work/lux/precompile/fhe/contract.go`
+   - `ciphertextStore` — no lock
+   - `ciphertextTypes` — no lock
+   - Pattern: every operation reads & writes → heavy R+W
+   - **Fix**: `sync.RWMutex` (reads are more frequent)
+     - `getCiphertext` called 2× per binary op → RLock
+     - `storeCiphertext` called 1× → Lock
+
+2. **attestation** — `/Users/z/work/lux/precompile/attestation/`
+   - `globalVerifier` — from `luxfi/ai` library, no visible internal locking
+   - `nvtrustVerifier` — same, no guard
+   - Library Verifier has internal mutable state (device registrations, job completions)
+   - **Fix**: Wrap calls in package-level `sync.RWMutex`, OR upstream the fix to `luxfi/ai`
+
+### Already protected (no fix needed)
+
+| Package | Lock | Notes |
+|---------|------|-------|
+| zk/stark.go | `starkVerifiersMu` | OK |
+| zk/pedersen.go | `sync.RWMutex` on pointCache + globalPedersen | OK |
+| zk/poseidon.go | `cacheMu` | OK |
+| zk/verifier.go | internal `mu` | OK |
+| frost | `liftXCacheMu` | OK |
+| quantum | `qv.mu` | OK |
+| dex | per-struct `mu`; HookSignatures read-only after init | OK |
+| bridge | gateway.go + signer.go have internal `mu` | OK |
+| graph | OracleQueries + AMMQueries + PredefinedQueries are read-only literals | OK |
+| ai | privacyMultipliers read-only; baseRewardPerMinute only `.Set()` reads | OK |
+| threshold | only error sentinels (immutable) | OK |
+
+## Implementation
+
+```go
+// fhe/contract.go additions:
+var (
+    ciphertextStoreMu sync.RWMutex
+    ciphertextStore   = make(map[string]*tfhe.Ciphertext)
+    ciphertextTypes   = make(map[string]int)
+)
+
+func storeCiphertext(key string, ct *tfhe.Ciphertext, fheType int) {
+    ciphertextStoreMu.Lock()
+    defer ciphertextStoreMu.Unlock()
+    ciphertextStore[key] = ct
+    ciphertextTypes[key] = fheType
+}
+
+func getCiphertext(key string) (*tfhe.Ciphertext, int, bool) {
+    ciphertextStoreMu.RLock()
+    defer ciphertextStoreMu.RUnlock()
+    ct, ok := ciphertextStore[key]
+    if !ok {
+        return nil, 0, false
+    }
+    return ct, ciphertextTypes[key], true
+}
+```
+
+## Test (must add)
+
+```go
+// fhe/concurrency_test.go
+func TestFHE_ConcurrentAccess(t *testing.T) {
+    const N = 100
+    var wg sync.WaitGroup
+    wg.Add(N)
+    for i := 0; i < N; i++ {
+        go func(i int) {
+            defer wg.Done()
+            // perform FHE op that reads+writes maps
+            _, _ = runFheOp(/* ... */)
+        }(i)
+    }
+    wg.Wait()
+}
+```
+
+Run with: `go test -race -run TestFHE_ConcurrentAccess`
+
+## Out-of-scope packages
+
+Per analysis, all other packages already have proper synchronization. Do NOT add mutexes where not needed — that's just noise.
+
+## Commits expected
+
+1. `fhe: add sync.RWMutex to ciphertextStore and ciphertextTypes (prevents consensus split)`
+2. `attestation: protect globalVerifier + nvtrustVerifier with sync.RWMutex`
+3. `precompile: add concurrency tests for fhe + attestation`