docs: the native-magic check covers files git reports as binary; attribute-text files are #3910

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

changelog.d/gst-972-review-exclude-follow-ups.md

@@ -1,7 +1,7 @@
 **`review_exclude_paths` keeps code it used to exclude, and the docs say exactly what the receipt check stops (GST-972).** Three ways to get code or a credential out of review under a base pattern are closed, each with a failing-first test in `test/review-exclude.test.ts`, and the receipt docs no longer over-claim.
 
 ### Fixed
-- **Native binaries are code.** A `.node`, `.so`, `.dylib` or `.dll` file under a base pattern was excluded as binary content, and so was a compiled executable with a data extension. A binary file now starting with ELF, Mach-O, PE, WebAssembly or `#!` magic is kept as `code` whatever its extension.
+- **Native binaries are code.** A `.node`, `.so`, `.dylib` or `.dll` file under a base pattern was excluded as binary content, and so was a compiled executable with a data extension. A file git reports as binary that starts with ELF, Mach-O, PE, WebAssembly or `#!` magic is now kept as `code` whatever its extension. A branch's `.gitattributes` can still make git read such a file as text, which skips the byte check (#3910).
 - **A NUL byte no longer makes code excludable.** A binary file was content unless its extension was on a short source list, so `.gradle`, `.sql`, `.tf`, `.groovy`, a `.p12` key store or an extensionless private key with a NUL byte was excluded. A binary file is now content only under a known content extension (images, fonts, media, documents, compressed archives, `.bin`, `.dat` and data blobs); every other binary file is kept as `code`.
 - **A branch's `.gitattributes` cannot get a file with a credential line excluded.** Marking `receipts/**` binary left the collector's added lines empty, so the secret-line keep rule saw nothing and the file was excluded. For a file git calls binary only because of its attributes, the rule now reads `git diff --text --no-textconv --no-ext-diff`, so the file stays in review and the plan lists it as `REVIEW_EXCLUDE_KEPT: secret-line`. Readers' own diffs still follow the branch's attributes and show that file as `Binary files differ`; reading such files as text in every reader's diff is a separate follow-up.
 - **`gstack-ship-receipt write --review-exclude` docs are exact.** The help, `docs/troubleshooting.md`, `docs/ship-policy.md` and the queue's refusal line said a receipt write alone cannot clear `field=review_exclude`. Write checks the digest against the base policy and does not read the review ledger, so a write given the refusal's `expected=` digest passes without a review. The text now says that, and that the review rerun is the fix.

docs/ship-policy.md

@@ -1287,7 +1287,7 @@ A pattern that matches no changed file is listed as `unmatched=` on the plan lin
 
 **What is excluded, and what is kept.** A matched file is excluded only when it
 is content: a data file (JSON, JSONL, CSV, TSV, images), a docs-class file, a
-`.log` file, or a file git reports as binary (`-\t-` in `--numstat`; readers would only see `Binary files differ`) whose bytes hold a NUL in their first 8,000, so a branch's `.gitattributes` cannot make a text file binary content. A binary file is content only under a known content extension (images, fonts, media, documents, compressed archives, `.bin`, `.dat`, and data blobs such as `.parquet`, `.npy` or `.sqlite`) and only when its bytes do not start with an executable image's magic (ELF, Mach-O, PE, WebAssembly, `#!`). Under those rules it is content even under
+`.log` file, or a file git reports as binary (`-\t-` in `--numstat`; readers would only see `Binary files differ`) whose bytes hold a NUL in their first 8,000, so a branch's `.gitattributes` cannot make a text file binary content. A binary file is content only under a known content extension (images, fonts, media, documents, compressed archives, `.bin`, `.dat`, and data blobs such as `.parquet`, `.npy` or `.sqlite`) and only when its bytes do not start with an executable image's magic (ELF, Mach-O, PE, WebAssembly, `#!`). Only files git reports as binary get this byte check, so a branch's `.gitattributes` that makes git read a file as text skips it (#3910). Under those rules it is content even under
 `config/` or in a skill directory, and only `policy-dir`, `gate-path`, `executable`, `link` or `gate-tagged` keep it. Every other binary file is `code`: source with a NUL, a native library (`.node`, `.so`, `.dylib`, `.dll`), a compiled executable, a key store, a pickle, or a file with no extension.
 Everything else stays in every reader's diff with one reason code: