The Remote Control HTTP tunnel validated each base64 message with a
backtracking regular expression. Requests larger than ~3.5MB (base64
~5MB) exhausted the V8 Irregexp backtracking stack and threw
RangeError, which the catch-all mapped to a 400 with an empty body,
surfacing as a generic connection failure on the web client.
Replace the regex with an O(n) character check, reject oversize
requests from the base64 length before decoding, and map non-SyntaxError
failures to 502 instead of 400.
* feat(remote-control): compress textual tunnel responses with gzip
* fix(remote-control): honor explicit gzip exclusion over accept-encoding wildcard
* fix(remote-control): skip gzip for 206 responses and vary by accept-encoding
* fix(remote-control): compress tunnel responses off the event loop
* fix(remote-control): vary identity responses and version compressed etags
* fix(remote-control): drop etags from gzipped tunnel responses
* fix(remote-control): release the lock before reporting off and re-read the server token per forward
* fix(remote-control): pass the token provider through the manager