bug: forge coverage not fully compatible with forge test commands

[zerosnacks]

Component

Forge

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

No response

What command(s) is the bug in?

forge coverage

Operating System

Linux

Describe the bug

Expected to be compatible with:

• --json (exits early)
• --watch (exits, does not watch Add support for --watch to forge coverage #4303)

Not expected but should be marked as incompatible:

• --junit
• --debug (is ignored), same for --framegraph and --flamechart
• --list (runs coverage but returns as 0% hitrate)

forge snapshot appears to be fully compatible

It is confusing that these options are available

[DaniPopes]

There are multiple JSON coverage formats (see https://docs.codecov.com/docs/supported-report-formats), and I don't think we should invent one for our own, so at the very least it should be a --format <some JSON format> flag.

[sakulstra]

uhh, format --json would be quite nice.
For aave dao we're currently using lcov-parse node package to transform from lcov.info to json.