## Summary
Adds global runtime flag to enable/disable MCP support. (off by
default).
```yaml
runtime_flags:
mcp: true
```
## Related issues
Fix:
https://linear.app/pomerium/issue/ENG-2367/place-mcp-support-behind-a-runtime-flag
## User Explanation
<!-- How would you explain this change to the user? If this
change doesn't create any user-facing changes, you can leave
this blank. If filled out, add the `docs` label -->
## Checklist
- [x] reference any related issues
- [ ] updated unit tests
- [ ] add appropriate label (`enhancement`, `bug`, `breaking`,
`dependencies`, `ci`)
- [ ] ready for review
Sort the runtime flag definitions alphabetically. Rename
envoy_resource_manager_enabled to just envoy_resource_manager for
consistency with the other flag names. (This flag hasn't been released
yet, so it should be OK to rename it.) Also add a doc comment.
* Initial envoy cgroup resource monitor implementation
* Add cgroupv1 support; add metrics instrumentation
* Slight refactor for more efficient memory limit detection
Instead of reading memory.max/limit_in_bytes on every tick, we
read it once, then again only when it is modified.
To support this change, logic for computing the saturation was moved out
of the cgroup driver and into the resource monitor, and the driver
interface now has separate methods for reading memory usage and limit.
* Code cleanup/lint fixes
* Add platform build tags
* Add unit tests
* Fix lint issues
* Add runtime flag to allow disabling resource monitor
* Clamp saturation values to the range [0.0, 1.0]
* Switch to x/sys/unix; handle inotify IN_IGNORED events
