docs: correct dig-mempool README and reserved error-variant docs

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dig-mempool"
-version = "0.1.1"
+version = "0.1.2"
 edition = "2021"
 rust-version = "1.75.0"
 description = "DIG L2 mempool — fee-prioritized, conflict-aware transaction pool with CPFP support"

README.md

@@ -1 +1,25 @@
-# dig-coinstate
+# dig-mempool
+
+A fee-prioritized, conflict-aware transaction mempool for the DIG Network L2
+blockchain.
+
+`dig-mempool` accepts raw `SpendBundle` submissions, validates them internally
+via [`dig-clvm`](../dig-clvm), and manages their lifecycle — fee ordering,
+conflict detection and replace-by-fee, timelock resolution, child-pays-for-parent
+(CPFP) packaging, and capacity eviction — then selects `MempoolItem`s for block
+candidate production. It does **not** build or validate blocks; that is the
+caller's responsibility.
+
+**Boundary:** inputs are `SpendBundle` + `CoinRecord`s; output is
+`Vec<Arc<MempoolItem>>`.
+
+## Documentation
+
+- [`SPEC.md`](docs/resources/SPEC.md) — the normative specification (wire model,
+  admission pipeline, conflict/RBF rules, CPFP semantics, fee tiers, invariants).
+- [`docs/requirements/README.md`](docs/requirements/README.md) — the requirement
+  catalog (61 requirements across 8 domains).
+
+## License
+
+See the repository root for license terms.

src/error.rs

@@ -107,18 +107,23 @@ pub enum MempoolError {
     InsufficientFee { required: u64, available: u64 },
 
     /// Fee-per-virtual-cost is too low for the current mempool utilization.
-    /// Returned when utilization >= 80% and the bundle doesn't meet the
-    /// minimum fee threshold from `estimate_min_fee()`.
+    ///
+    /// Reserved for utilization-based admission rejection: `estimate_min_fee()`
+    /// is currently advisory only and admission does not enforce it, so this
+    /// variant is **not currently constructed**.
     /// See: [FEE-001](docs/requirements/domains/fee_estimation/specs/FEE-001.md)
     #[error("fee too low for current mempool utilization")]
     FeeTooLow,
 
     // ── Conflict / RBF Errors ──
     // See: [CFR-001](docs/requirements/domains/conflict_resolution/specs/CFR-001.md)
     //      through [CFR-005](docs/requirements/domains/conflict_resolution/specs/CFR-005.md)
-    /// A coin spent by this bundle is already spent by an active mempool item,
-    /// and the RBF conditions were not met. The bundle has been added to the
-    /// conflict cache for retry after the conflicting item is confirmed.
+    /// A coin spent by this bundle is already spent by an active mempool item
+    /// and the RBF conditions were not met.
+    ///
+    /// Reserved: unmet-RBF conflicts are currently surfaced through the specific
+    /// `Rbf*` variants below (superset / fee-per-cost / bump), so this catch-all
+    /// is **not currently constructed**.
     /// Chia: `MEMPOOL_CONFLICT` at [mempool_manager.py:816](https://github.com/Chia-Network/chia-blockchain/blob/6e7a4954edccd8ab83fcacf938cfc42ddfcad7f2/chia/full_node/mempool_manager.py#L816).
     #[error("conflicts with existing mempool item {0}")]
     Conflict(Bytes32),