feat(telemetry): flow events foundations

[LorrisSaintGenez]

What

Foundations for the CLI flow events (GROUT-349), one atomic commit per step:

1. Telemetry client lifecycle fix — go telemetryClient.Close() ran in PersistentPreRunE, closing the client before the command executed and racing with process exit. The client is now closed via defer in Execute(), bounded by a 3s timeout so an unreachable telemetry endpoint never delays exit. createContext falls back to NoOpTelemetryClient instead of storing a nil interface, and analytics-go Verbose logging is enabled in debug mode.
2. Track with custom properties + sequence — Track(ctx, event, properties) merges custom properties with the base ones (base written last, so call sites cannot override them). Every event carries a monotonic sequence (atomic counter): the exact order of one invocation can be reconstructed downstream by sorting on (invocation_id, sequence) — Segment stores millisecond-precision timestamps, so back-to-back events can tie.
3. Event catalog + Command Completed — pkg/telemetry/events.go holds the event name constants, the Flow/Step/Direction enums, FlowTracker (current step + flow duration) and ErrorClass (first informative type of the error chain, never the error message). Execute() now emits Command Completed (succeeded, exit_code, duration_ms, plus error_class/user_cancelled on failure) right before the final flush.
4. Independent review fixes — no orphan Command Completed when PersistentPreRunE never ran (--help, --version, unknown flag/command, failed auth check: no paired Command Invoked, and the command property would be empty); duration_ms is measured right after execution so it never includes the update-notifier wait; tests for trackCommandCompleted and for sequence uniqueness under concurrency.

Test

# network on: verbose telemetry logs show the final batch
# (Identify + Command Invoked + Command Completed)
DEBUG=1 go run ./cmd/algolia application plans

# network off: the command fails on its own network error,
# exit adds at most ~3s for the telemetry flush (no hang)
time DEBUG=1 go run ./cmd/algolia application plans

# no telemetry at all for --help / --version / typos
DEBUG=1 go run ./cmd/algolia --help
DEBUG=1 go run ./cmd/algolia doesnotexist

GROUT-349

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 19 complexity · 16 duplication

Metric	Results
Complexity	19
Duplication	16

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_{TIP This summary will be updated as you push new changes.}