flake: replace naersk with crane (#538)

Framework swap, no public API change.

- naersk input → crane (`github:ipetkov/crane`); crane is stateless, no
  nixpkgs.follows needed.
- `forAllSystems` exposes `craneLib = crane.mkLib pkgs`,
  `cargoArtifacts = craneLib.buildDepsOnly` (built once, reused), and
  a shared `nativeBuildInputs = [ pkgs.librsvg pkgs.git ]` consumed by
  buildDepsOnly + buildPackage + cargoClippy so the three derivations
  see the same toolchain shape.
- `packages.default = craneLib.buildPackage` (was naersk-lib.buildPackage)
  with explicit `pname = "hyperhive-workspace"; version = "0.1.0";` —
  the virtual workspace Cargo.toml has no [package].name so crane
  needs the hint.
- `checks.clippy = craneLib.cargoClippy` (was naersk + overrideAttrs
  hack). Crane parses `cargoClippyExtraArgs = "--workspace --all-targets
  -- -D warnings"` correctly; naersk's `mode = "clippy"` used to mangle
  the `--` separator which is why the old wiring went through
  overrideAttrs. The whole hack — including `doCheck = false`,
  `copyTarget = false`, and the swapped buildPhase/installPhase — is
  now gone.
- librsvg native dep (#424) preserved on all three derivations. Added
  pkgs.git too — naersk auto-included it; crane is more minimal, so
  hive-c0re's `lifecycle::tests::setup_proposed_*` (which shell out to
  `git init`+commit) need it explicit to pass under `cargo test` in
  the sandbox.
- build.rs + hive-c0re/Cargo.toml comments updated from "naersk
  derivation" to "crane derivation".
- 3 doc-list-indentation lints in hive-sh4re/src/lib.rs cleaned up
  (replaced `+`-at-line-start with `and`/`/` so doc continuations
  don't trigger `clippy::doc_lazy_continuation`).

Validated locally: `nix build .#default --fallback` succeeds, all
117 tests pass, all four bins in `result/bin/`.

flake.lock

@@ -1,45 +1,17 @@
 {
   "nodes": {
-    "fenix": {
-      "inputs": {
-        "nixpkgs": [
-          "naersk",
-          "nixpkgs"
-        ],
-        "rust-analyzer-src": "rust-analyzer-src"
-      },
+    "crane": {
       "locked": {
-        "lastModified": 1752475459,
-        "narHash": "sha256-z6QEu4ZFuHiqdOPbYss4/Q8B0BFhacR8ts6jO/F/aOU=",
-        "owner": "nix-community",
-        "repo": "fenix",
-        "rev": "bf0d6f70f4c9a9cf8845f992105652173f4b617f",
+        "lastModified": 1779130139,
+        "narHash": "sha256-BLrtr42azquO7MdGFU5a7KiMl3YpFlTeIXqy1fT5GlQ=",
+        "owner": "ipetkov",
+        "repo": "crane",
+        "rev": "edb38893982a3338972bb4a2ec7ce7c29ba10fd9",
         "type": "github"
       },
       "original": {
-        "owner": "nix-community",
-        "repo": "fenix",
-        "type": "github"
-      }
-    },
-    "naersk": {
-      "inputs": {
-        "fenix": "fenix",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1778151388,
-        "narHash": "sha256-lldMJPUeouEjO8/7aLuwhcsIw29vVihm2ZALzjiqfec=",
-        "owner": "nix-community",
-        "repo": "naersk",
-        "rev": "efdddff9ff4d8e7d0056d57ec67dac50f75ab8f6",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "naersk",
+        "owner": "ipetkov",
+        "repo": "crane",
         "type": "github"
       }
     },
@@ -77,29 +49,12 @@
     },
     "root": {
       "inputs": {
-        "naersk": "naersk",
+        "crane": "crane",
         "nixpkgs": "nixpkgs",
         "nixpkgs-unstable": "nixpkgs-unstable",
         "treefmt-nix": "treefmt-nix"
       }
     },
-    "rust-analyzer-src": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1752428706,
-        "narHash": "sha256-EJcdxw3aXfP8Ex1Nm3s0awyH9egQvB2Gu+QEnJn2Sfg=",
-        "owner": "rust-lang",
-        "repo": "rust-analyzer",
-        "rev": "591e3b7624be97e4443ea7b5542c191311aa141d",
-        "type": "github"
-      },
-      "original": {
-        "owner": "rust-lang",
-        "ref": "nightly",
-        "repo": "rust-analyzer",
-        "type": "github"
-      }
-    },
     "treefmt-nix": {
       "inputs": {
         "nixpkgs": [