The wide diff's context drops from 200 to 25 lines, so a block's
enclosing gate stays in view when it opens within 25 lines above the
change (the forge's own diff carries 3). The fallback note, the doc and
the gate fixture (now 20 lines out, not 47) follow.
A failure reading the changed files (a forge error on a tree or blob, a
truncated tree, a non-base64 blob) or joining the diff task made the PR
read fail, so the review posted no verdict. It now falls back to the
forge's 3-line .diff with "reading the files failed: …" as the note.
render wrote each file's whole diff before wide compared it with
MAX_BYTES. It now writes through a writer that refuses once past the cap,
which stops similar's formatter mid-file, so one huge file costs about
MAX_BYTES of output, not its full diff.
The classifier read the forge's PR `.diff`, whose context is fixed at 3
lines. A block moved into a glue module lost its enclosing gate (a
`config = lib.mkIf …` 13 to 191 lines up in the misfired moves #5199,
#5200, #5201), so the glue restating that gate read as a new condition.
The controller now builds the diff itself: it lists the PR's changed files,
reads each at the merge base and at the head through the git tree and blob
API with the token it already holds, and diffs them with 200 lines of
context. It sends the forge's `.diff` instead when the PR changes more than
100 files, the forge names no merge base, or the wide diff is over 256 KiB,
and the posted review then says so with the reason.
Fixes#5227
