Clean up migration output

[computermode]

Cleans up the migration output such that it's a prettier progress bar rather than a long list of logged checkpoints. It prints out the # of checkpoints that were migrated, skipped, or failed at the end (and mentions where to find more info if needed in the logs).

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Note

Medium Risk
Mostly changes user-facing output and observability for v1→v2 checkpoint migration, but it refactors migration control flow and return values (e.g., backfill/repair outcomes) which could subtly affect migration counting and error handling.

Overview
Refactors v1→v2 checkpoint migration output to be quiet by default: migration now renders a terminal progress bar (to stderr) and prints only a final completion summary, with skip/missing/compaction/backfill/repair details written to .entire/logs/entire.log.

Migration now tracks richer results (missingSessions, compactTranscriptSkipped, backfilledCompactTranscripts, repaired) and converts previously printed per-checkpoint warnings/notes into structured log entries; backfillCompactTranscripts also returns a backfilled count instead of printing output.

Updates tests to assert on the new result counters and the absence/presence of stdout text, and adds printMigrateCompletion coverage for when log-path guidance should be shown.

^{Reviewed by Cursor Bugbot for commit 8b4404b. Configure here.}

[Copilot]

Pull request overview

This PR refines the entire migrate --checkpoints v2 UX by suppressing per-checkpoint stdout chatter, showing terminal-friendly progress, and printing a concise completion summary with aggregate counts and guidance on where to find details.

Changes:

• Added a terminal-aware progress bar helper for long-running CLI operations.
• Refactored v1→v2 migration to write detailed per-checkpoint outcomes to structured logs instead of stdout, while tracking additional outcome counters.
• Updated migration tests to assert quiet stdout and added unit tests for the completion-summary messaging.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
cmd/entire/cli/progress.go	Adds a simple progress bar implementation for terminal writers.
cmd/entire/cli/migrate.go	Reworks migration output: progress on stderr, summary on stdout, detailed info via logging, and adds richer result accounting.
cmd/entire/cli/migrate_test.go	Updates expectations for quiet stdout and adds coverage for the completion summary behavior.