💡 sign macOS release binaries

**Describe the feature you'd like**
The `cloudflared` binaries available for macOS via Homebrew / GitHub Releases are currently distributed without code signing.

```sh
codesign -dvv /opt/homebrew/bin/cloudflared

Executable=/opt/homebrew/Cellar/cloudflared/2026.7.3/bin/cloudflared
Identifier=a.out
Format=Mach-O thin (arm64)
CodeDirectory v=20400 size=296926 flags=0x20002(adhoc,linker-signed) hashes=9276+0 location=embedded
Signature=adhoc
Info.plist=not bound
TeamIdentifier=not set
Sealed Resources=none
Internal requirements=none
```

Wondering if this has been explored as an option for making `cloudflared` a trusted binary on macOS?

**Additional context**
To reduce risks posed by the execution of untrusted binaries, enterprises environments are beginning to enforce aggressive binary authorisation policies that restrict the execution of unsigned code. Having `cloudflared` signed with a Developer ID certificate would allow folks to maintain these policies without disrupting engineers' workflows.

Start by reviewing how cloudflared binaries are built and distributed through GitHub Releases and Homebrew; the issue does not name specific files or tests. Determine what release-process changes would be needed to sign macOS binaries with a Developer ID certificate. Done means the distributed macOS binaries carry a verifiable signature.

Written by the indexing model from the issue text.