Closes#1820.
The container agent-runner sets CLAUDE_CODE_AUTO_COMPACT_WINDOW
unconditionally on the container process env, with no way to override
it per-deployment without editing source. Read process.env first and
fall back to the existing 165000 literal when unset.
Default behavior is unchanged for installs that do not set the env
var. Operators running 1M-context models or emergency-tuning a live
deployment can now raise or lower the threshold from the host env.
When a channel bridge passes an attachment without an explicit `name`,
extractAttachmentFiles fell back to `attachment-<ts>` with no extension.
Agents could not tell whether the file was a JPEG, PDF, or audio clip,
and tools keyed on extension (image viewers, exiftool, etc.) misbehaved.
Two cases are now covered:
1. Channels that set `mimeType` but no `name` (Discord/Slack documents,
Telegram document uploads). A small MIME-to-extension table covers
the common content types — image/*, audio/*, video/*, pdf, zip,
txt, json. Unknown MIMEs fall back to the unsuffixed name.
2. Channels that set `att.type` but no `mimeType` (Telegram photos,
stickers, voice, animations). The chat-sdk bridge sets a coarse
media-class (`photo` / `sticker` / `voice` / `video` /
`animation`) which is reliable enough to derive a canonical
extension. Telegram GIFs are MP4 under the hood.
The existing isSafeAttachmentName security guard is preserved — the
derived name still passes through it before disk I/O. The new lookup
tables emit static values from internal maps and cannot construct a
path-traversal payload; attacker-controlled att.name continues to flow
through the same validator.
robbyczgw-cla