Build with Go 1.24.4

Adds middleware that sets X-Request-Start header with millisecond timestamp
for request timing measurement. Header format follows convention
of t=<milliseconds_since_epoch>.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Add X-Request-Start header middleware

When using custom response writers in middleware, we need to ensure they
all implement `http.Flusher`. Otherwise, the resulting handler will not
be flushable, which means the reverse proxy has no way to flush response
content to the client.

Not being able to flush content breaks response types like SSE, which
depend on sending chunked data as it happens, rather than buffering it
all to the end.

Adds an environment variable, $LOG_REQUESTS, that when set to a falsey
value will not add the logging middleware to the HTTP handler, disabling
request logs. Other logs, like the startup messages, are left alone.

Closes #49.

Teach thruster to optionally not log requests

Add host to cache key

Ensure all response writers are flushable