Check coverage on `init()` in CoverAgent

[EmbeddedDevops1]

Summary

We used to check coverage during init() and track the initial coverage state, but this was removed. We need to:

• Check initial coverage against the desired coverage on init().
• Store that initial coverage in a class attribute, which should never be modified after it’s set.

Requirements

1. Perform a coverage check as soon as init() completes.
2. If initial coverage meets or exceeds the desired coverage, handle that scenario appropriately (e.g., may not need further iterations).
3. Store the initial coverage in a read-only class attribute (immutable after assignment).

Acceptance Criteria

• A coverage check happens in init().
• An immutable attribute holds the initial coverage value.
• Existing logic uses (but does not alter) the stored initial coverage.
• All tests pass without regressions.