feat(event-streams): improve subscribe UX

[developerkunal]

🔧 Changes

Improves the auth0 event-streams subscribe UX so live event inspection is easier to read, easier to interrupt, and easier to resume, and keeps long-lived sessions alive across the server's periodic connection rotations.

Discoverability

• --list-event-types prints every value accepted by --event-type and exits without opening a subscription.
• Invalid --event-type values are now collected up front and reported in a single error listing every bad value, instead of bailing on the first. The error points at --list-event-types for the full list, and the SDK's internal Go type name no longer leaks into user output.

Reconnect behavior

• The server rotates long-lived SSE connections every few minutes. Previously this exhausted the SDK's lifetime reconnect cap and the session silently ended. The command now owns reconnection via a CLI-level resume loop that re-subscribes from the last cursor, so the session stays continuous and no events are missed.
• Reconnect delay is exponential backoff with full jitter, accrued only on consecutive zero-progress failures; any forward progress resets it, so healthy rotations reconnect instantly and silently. The server-advertised SSE retry: directive is honored as a floor, and a 1s minimum interval between attempts prevents a flapping connection from spinning in a tight loop.
• --no-reconnect exits cleanly when the connection ends instead of resuming.
• --max-reconnects N caps consecutive failed reconnect attempts before giving up (0 = retry indefinitely while progress is being made). Mutually exclusive with --no-reconnect.
• Ctrl+C cancels via context so the disconnect summary always prints.

Output cleanups

• connection_timeout frames (a protocol artifact emitted right before the server drops the SSE connection) are filtered up front, so the rendered output, --json / --json-compact, and the --output-file capture all stay consistent and free of reconnect noise.
• Server-emitted error events (rate limits, auth, etc.) render on their own row, are tracked in a separate Errors: counter in the summary, and no longer pollute per-type event counts.
• The disconnect summary now reports session duration, an Errors: line when non-zero, and groups per-type counts under a By type: heading, sorted by count desc with aligned columns.
• Event rows align: type and source pad to fixed widths before ANSI coloring so escape codes don't break visual alignment. Event IDs and error messages stay full-length so nothing forensic is truncated.
• The resume hint prints as a single line so the cursor is easy to copy.

Bumps

• github.com/auth0/go-auth0/v2: v2.11.0 → v2.12.0.

📚 References

None.

🔬 Testing

Unit tests added in internal/cli/event_streams_subscribe_test.go covering the pure helpers:

• summarizeEvent for heartbeat, error, connection_timeout, and concrete-event envelope variants.
• padRight for short, equal, long, and empty inputs.
• shortOffset for short, boundary, and long cursor truncation.
• colorForEventType confirms the original type string survives the color wrap for every suffix branch plus error and unknown.
• invalidEventTypesError covers single-value and multi-value cases, plus a guard that the SDK's internal type name never leaks into user output.
• reconnectBackoff confirms an immediate reconnect on a healthy rotation, that jittered delays stay within their exponential ceiling and never exceed the 30s cap, and that the server retry: directive acts as a floor.

Run with:

go test ./internal/cli/ -run 'TestSummarizeEvent|TestPadRight|TestShortOffset|TestColorForEventType|TestInvalidEventTypesError|TestReconnectBackoff'

Manual end-to-end testing against a live tenant:

• auth0 event-streams subscribe left running across multiple server connection rotations to confirm the session stays continuous with no event loss and no reconnect noise, then Ctrl+C to confirm the summary shows duration, event counts, errors when any, heartbeats, the By type: block, and a readable resume hint.
• auth0 event-streams subscribe --list-event-types to confirm the full list prints and the command exits.
• auth0 event-streams subscribe --event-type bad.value --event-type also.bad to confirm both bad values are reported in one error.
• auth0 event-streams subscribe --no-reconnect and --max-reconnects 1 to confirm both flags are accepted and mutually exclusive.

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[ramya18101]

We are adding lastOffSet twice in the output.. one in the info and another in the output command.. Can this be reverted..?