Fix convoy close dedup after reopen

[seanwessmith]

Summary

• allow convoy close detection to recover after an issue is reopened and closed again
• add a 1-second event poll overlap plus lifecycle event-id dedup to handle Dolt's second-precision timestamps without replaying old close events
• preserve warm-up semantics and add regressions for reopen/reclose across polls and within one poll

Testing

• go test ./internal/daemon

[codecov-commenter]

❌ 4 Tests Failed:

Tests completed	Failed	Passed	Skipped
9321	4	9317	48

View the top 3 failed test(s) by shortest run time

github.com/steveyegge/gastown/internal/cmd::TestFindWLCommonsFork_NoDoltDir

Stack Traces | 0s run time

=== RUN   TestFindWLCommonsFork_NoDoltDir
=== PAUSE TestFindWLCommonsFork_NoDoltDir
=== CONT  TestFindWLCommonsFork_NoDoltDir
    testing.go:1712: race detected during execution of test
--- FAIL: TestFindWLCommonsFork_NoDoltDir (0.00s)

github.com/steveyegge/gastown/internal/cmd::TestStampLoop_EndToEnd

Stack Traces | 0s run time

=== RUN   TestStampLoop_EndToEnd
=== PAUSE TestStampLoop_EndToEnd
=== CONT  TestStampLoop_EndToEnd
    testing.go:1712: race detected during execution of test
--- FAIL: TestStampLoop_EndToEnd (0.00s)

github.com/steveyegge/gastown/internal/cmd::TestStampLoop_InvalidValence

Stack Traces | 0s run time

=== RUN   TestStampLoop_InvalidValence
=== PAUSE TestStampLoop_InvalidValence
=== CONT  TestStampLoop_InvalidValence
--- FAIL: TestStampLoop_InvalidValence (0.00s)

github.com/steveyegge/gastown/internal/cmd::TestStampLoop_InvalidValence/quality_negative

Stack Traces | 0s run time

=== RUN   TestStampLoop_InvalidValence/quality_negative
    testing.go:1712: race detected during execution of test
--- FAIL: TestStampLoop_InvalidValence/quality_negative (0.00s)

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[steveyegge]

Fix-merged to main (rebased and pushed directly). Convoy close-reopen-close dedup fix is solid — good edge case handling.