feat: add scorer-inspect crate with text/csv/json output

scorer-inspect is a small standalone CLI for offline diagnostics of LDK
serialized scorer files - both the `latest.bin` style payloads served at
URLs like api.blocktank.to/scorer-prod or scores.zeusln.com/latest.bin
and the bytes returned by Node::export_pathfinding_scores. Both wire
formats are identical in current LDK (ProbabilisticScorer::write just
delegates to ChannelLiquidities::write), so the parser is a single
ChannelLiquidities::read; the --source flag is metadata only.

Output is configurable as plain text (default), CSV, or pretty-printed
JSON, optionally written to disk via --save. The summary section
reports entry count, history-populated percentage, and offset / bucket
weight distributions; the per-channel section can be limited via --top
or fully dumped via --all, and sorted by narrowest offset window,
recency, or historical bucket weight.

Depends on the diagnostics() accessors added to ChannelLiquidities and
ProbabilisticScorer in the synonymdev/rust-lightning fork. The ldk-node
[patch.crates-io] block is unchanged here; the rust-lightning PR must
land first and the rev pin must be bumped before this branch can merge.
For local development of this crate, point [patch.crates-io] at a
checkout of synonymdev/rust-lightning that has the diagnostics
accessors applied.

Author: ovitrif

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = [".", "crates/bdk-wallet-aggregate"]
+members = [".", "crates/bdk-wallet-aggregate", "crates/scorer-inspect"]
 exclude = ["bindings/uniffi-bindgen"]
 
 [package]

crates/scorer-inspect/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "scorer-inspect"
+version = "0.1.0"
+edition = "2021"
+rust-version = "1.85"
+description = "Offline diagnostics CLI for LDK ProbabilisticScorer / ChannelLiquidities files."
+license = "MIT OR Apache-2.0"
+
+[dependencies]
+anyhow = "1"
+clap = { version = "4", features = ["derive"] }
+csv = "1"
+humansize = "2"
+lightning = { version = "0.2.0", features = ["std"] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"

crates/scorer-inspect/README.md

@@ -0,0 +1,69 @@
+# scorer-inspect
+
+Offline diagnostics CLI for LDK serialized scorer files.
+
+Reads a binary file produced by either:
+- LDK's external scorer / `ProbabilisticScorer::write` (e.g. `https://api.blocktank.to/scorer-prod`, `https://scores.zeusln.com/latest.bin`), or
+- ldk-node's `Node::export_pathfinding_scores`.
+
+Both wire formats are identical in current LDK — `ProbabilisticScorer::write` just calls `self.channel_liquidities.write(w)`. The tool always reads via `ChannelLiquidities::read` and the `--source` flag is purely metadata for the report.
+
+## Build
+
+```
+cargo build -p scorer-inspect --release
+```
+
+## Usage
+
+```
+scorer-inspect <FILE>
+  [--source served|exported]
+  [--output text|csv|json]
+  [--save PATH]
+  [--top N]
+  [--all]
+  [--sort narrow|recent|history]
+```
+
+- `--source` — annotates the report; doesn't affect parsing.
+- `--output text` (default) — short summary + top-N channel rows for human review.
+- `--output csv` — summary row, blank line, then one row per channel. Editor-friendly.
+- `--output json` — `{ summary: {...}, channels: [...] }`. Machine-readable.
+- `--save PATH` — write to file instead of stdout.
+- `--top N` (default 20) — limit channel rows.
+- `--all` — dump every entry; overrides `--top`.
+- `--sort` — `narrow` (smallest offset window first; highest information density), `recent` (most recently updated first), `history` (largest historical-bucket weight first; most probe-derived signal).
+
+## Examples
+
+```
+# Quick eyeball of Zeus's served file
+curl -o /tmp/zeus.bin https://scores.zeusln.com/latest.bin
+scorer-inspect /tmp/zeus.bin --source served
+
+# Full per-channel CSV diff between Zeus and Bitkit
+curl -o /tmp/blocktank.bin https://api.blocktank.to/scorer-prod
+scorer-inspect /tmp/zeus.bin       --source served --all --output csv --save /tmp/zeus.csv
+scorer-inspect /tmp/blocktank.bin  --source served --all --output csv --save /tmp/blocktank.csv
+```
+
+## What the columns mean
+
+- `min_liquidity_offset_msat` / `max_liquidity_offset_msat` — non-directional offsets relative to the channel's node ordering. Resolving them into directional `min_liquidity_sat` / `max_liquidity_sat` requires a `NetworkGraph` (capacity + node-id ordering), which this tool doesn't yet take.
+- `has_history` — whether either historical-bucket array is non-zero. The single best signal for distinguishing probe-derived data from synthetic graph seeding.
+- `total_valid_points_tracked` (CSV/JSON), `history_weight` (text) — LDK-internal scalar weight summarizing the historical bucket distribution. Stored as `f64`; not an integer payment count.
+- `last_updated_secs` — seconds since the unix epoch when either liquidity bound was last modified.
+
+## Distinguishing rich probe data from synthetic seeding
+
+A scorer file can be large for two very different reasons:
+
+- **Probe-rich**: many entries with `has_history=true`, narrow `[min_offset, max_offset]` windows, sizable `total_valid_points_tracked`. This is what real probing produces.
+- **Synthetic-coverage**: many entries with `has_history=false`, `min_offset=0`, `max_offset` close to channel capacity, zero bucket weights. This is what gossip-graph seeding produces — big file, low pathfinding signal.
+
+Compare the two by running the tool against any scorer file and checking the `history populated` percentage and the offset-window distribution.
+
+## Limits
+
+- v1 is graph-free: directional output and capacity-resolved sats are not available without a `NetworkGraph`. Adding `--graph PATH` is tracked as future work.