feat: add eventually-with-t checker

[mmorel-35]

assert.EventuallyWithT provides a *assert.CollectT to the callback for accumulating failures across retries. Using the outer t or require bypasses this mechanism — require calls runtime.Goexit(), killing the tick entirely instead of collecting failures.

New checker: eventually-with-t (enabled by default)

Three violation patterns are detected:

Pattern	Autofix
assert.xxx(outerT, ...) — outer t passed instead of collect	✅ replaces arg with collect param name
require.xxx(outerT, ...) — require semantics differ from assert	❌ report only
Assertion object (a := assert.New(t)) used inside callback	❌ report only

a := assert.New(t)
assert.EventuallyWithT(t, func(collect *assert.CollectT) {
    assert.Equal(t, expected, actual)  // ❌ autofix → assert.Equal(collect, ...)
    require.NoError(t, err)            // ❌ use assert.NoError(collect, err)
    a.Equal(expected, actual)          // ❌ a was created with outer t
}, timeout, interval)

Handles both package-level calls (assert.Equal(t, ...)) and assertion-object calls (a.Equal(...)). Nested function literals inside the callback are intentionally excluded to avoid false positives in goroutines or sub-tests.

Closes #284