0.8.0: bump Cargo.toml + CHANGELOG + module-doc version refs

Cuts the 0.8.0 release branch. Tagging and publishing held for explicit
trigger; this commit is local-only and only updates version metadata.

Cargo.toml: 0.7.2 -> 0.8.0
CHANGELOG.md: new [0.8.0] - 2026-04-27 section under Keep-a-Changelog
  format. Documents the two breaking changes (esg -> range_filtered
  rename + spectral pub -> pub(crate)) under "Changed (breaking)" and
  includes a diff-style migration block from 0.7.x.
src/lib.rs install snippet + 19 module-level //! doc snippets bumped
  from `version = "0.7"` to `version = "0.8"`. README install block
  unchanged (was already 0.7-pinned; bumped to 0.8 in the same sweep).

Verification at this commit:
  cargo fmt --check                                           clean
  cargo clippy --no-default-features --features hnsw --all-targets -- -D warnings
                                                              clean
  cargo clippy --all-features --all-targets -- -D warnings    clean
  cargo nextest run --no-default-features --features hnsw     314/314 pass
  cargo nextest run --lib --all-features                      400/400 pass

Tag + publish workflow trigger held: per personal-style rule, version
bumps only land in-tree when about to publish, but the user wants the
release-ready state captured. Next step is `git tag v0.8.0 && git push
--tags` followed by `gh workflow run publish.yml -f confirm=publish`,
gated on user say-so.

Author: arclabs561

CHANGELOG.md

@@ -7,6 +7,47 @@ series is unstable: minor bumps may break the public API.
 
 ## [Unreleased]
 
+## [0.8.0] - 2026-04-27
+
+### Changed (breaking)
+
+- Renamed `esg` module to `range_filtered`. The 0.7.x `esg` name implied
+  fidelity to the partition-aware structure of Yang et al. 2025
+  (arXiv:2504.04018); the shipped implementation is the paper's
+  strawman baseline (HNSW + attribute-range post-filter), so the rename
+  reflects what the module actually does. A paper-fidelity ESG variant
+  is planned as a separate module.
+  - `EsgIndex` -> `RangeFilteredIndex`
+  - `EsgParams` -> `RangeFilteredParams`
+  - feature `esg` -> `range_filtered`
+  - module path `vicinity::esg::*` -> `vicinity::range_filtered::*`
+  - `RangeFilteredParams::num_checkpoints` removed (was deprecated in
+    0.7.3; the partition-aware path that consumed it was never
+    implemented).
+- `vicinity::spectral` module visibility downgraded from `pub` to
+  `pub(crate)`. The Marchenko-Pastur helpers were reachable only via
+  `ADSamplingState::new_auto`, which has no production consumer. The
+  `rmt-spectral` feature and the `rmt` dep remain available for the
+  internal `new_auto` path; the public wrappers `mp_lambda_plus` and
+  `count_mp_outliers` are no longer accessible from outside the crate.
+
+### Migration from 0.7.x
+
+```diff
+-vicinity = { version = "0.7", features = ["esg"] }
++vicinity = { version = "0.8", features = ["range_filtered"] }
+
+-use vicinity::esg::{EsgIndex, EsgParams};
++use vicinity::range_filtered::{RangeFilteredIndex, RangeFilteredParams};
+
+ let params = EsgParams {
+-    num_checkpoints: 16,  // remove
+     hnsw_m: 16,
+     hnsw_ef_construction: 200,
+     ef_search: 100,
+ };
+```
+
 ## [0.7.2] - 2026-04-27
 
 ### Changed

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "vicinity"
-version = "0.7.2"
+version = "0.8.0"
 authors = ["Arc <attobop@gmail.com>"]
 edition = "2021"
 rust-version = "1.89"

README.md

@@ -37,9 +37,9 @@ Each algorithm is a separate feature. Enable what you need:
 
 ```toml
 [dependencies]
-vicinity = { version = "0.7", features = ["hnsw"] }          # graph index
-# vicinity = { version = "0.7", features = ["ivf_pq"] }      # compressed index
-# vicinity = { version = "0.7", features = ["nsw"] }         # flat graph
+vicinity = { version = "0.8", features = ["hnsw"] }          # graph index
+# vicinity = { version = "0.8", features = ["ivf_pq"] }      # compressed index
+# vicinity = { version = "0.8", features = ["nsw"] }         # flat graph
 ```
 
 ## Usage
@@ -82,7 +82,7 @@ Save and load indexes with the `serde` feature:
 
 ```toml
 [dependencies]
-vicinity = { version = "0.7", features = ["hnsw", "serde"] }
+vicinity = { version = "0.8", features = ["hnsw", "serde"] }
 ```
 
 ```rust

src/binary_index/mod.rs

@@ -13,7 +13,7 @@
 //! # Feature Flag
 //!
 //! ```toml
-//! vicinity = { version = "0.7", features = ["binary_index"] }
+//! vicinity = { version = "0.8", features = ["binary_index"] }
 //! ```
 //!
 //! # Quick Start

src/curator/mod.rs

@@ -9,7 +9,7 @@
 //! # Feature Flag
 //!
 //! ```toml
-//! vicinity = { version = "0.7", features = ["curator"] }
+//! vicinity = { version = "0.8", features = ["curator"] }
 //! ```
 //!
 //! # Quick Start

src/diskann/mod.rs

@@ -9,7 +9,7 @@
 //! # Feature Flag
 //!
 //! ```toml
-//! vicinity = { version = "0.7", features = ["diskann"] }
+//! vicinity = { version = "0.8", features = ["diskann"] }
 //! ```
 //!
 //! # Status: Experimental

src/emg/mod.rs

@@ -9,7 +9,7 @@
 //! # Feature Flag
 //!
 //! ```toml
-//! vicinity = { version = "0.7", features = ["emg"] }
+//! vicinity = { version = "0.8", features = ["emg"] }
 //! ```
 //!
 //! # Quick Start

src/filtered_graph/mod.rs

@@ -14,7 +14,7 @@
 //! # Feature Flag
 //!
 //! ```toml
-//! vicinity = { version = "0.7", features = ["filtered_graph"] }
+//! vicinity = { version = "0.8", features = ["filtered_graph"] }
 //! ```
 //!
 //! # Quick Start

src/finger/mod.rs

@@ -10,7 +10,7 @@
 //! # Feature Flag
 //!
 //! ```toml
-//! vicinity = { version = "0.7", features = ["finger"] }
+//! vicinity = { version = "0.8", features = ["finger"] }
 //! ```
 //!
 //! # Quick Start

src/fresh_graph/mod.rs

@@ -10,7 +10,7 @@
 //! # Feature Flag
 //!
 //! ```toml
-//! vicinity = { version = "0.7", features = ["fresh_graph"] }
+//! vicinity = { version = "0.8", features = ["fresh_graph"] }
 //! ```
 //!
 //! # Quick Start