feat(installed): Align install and session lifecycle with new schema

[CSRessel]

Motivation

• Standardize install/session lifecycle tracking and analytics payloads so Nori CLI reports (install, update, churn/resurrection) match the shared analytics endpoint and GA dashboards.
• Make client identity deterministic and privacy-preserving so churn/resurrection measurements remain consistent after config resets while preserving opt-out control.
• Ensure events are non-blocking and follow a unified flat JSON schema with session-scoped fields for downstream aggregation and performance constraints.

Description

• Replace the previous user-id approach with a deterministic client UUID generated from SHA256("nori_salt:<hostname>:<username>") and persist it as client_id in the state file, and add an opt_out boolean to the state schema saved at $NORI_HOME/.nori-install.json.
• Expand lifecycle events to emit app_install, app_update, user_resurrected (if last launch > 30 days), and session_start, generate an ephemeral session_id per run, and use semver comparison (via semver crate) to detect upgrades.
• Rework analytics payloads to a flat JSON event with event, client_id, session_id, timestamp, and properties (version/os/arch/node_version/is_ci), send to NORI_ANALYTICS_URL (default https://noriskillsets.dev/api/analytics/track) with a 500ms timeout, fire-and-forget behavior, and silent failure handling.
• Honor opt-out precedence: NORI_NO_ANALYTICS=1 wins, otherwise the opt_out field in .nori-install.json prevents network sends while still updating local state timestamps atomically (temp file + rename preserved).
• Updated code, docs, and dependencies: added semver and uuid, updated installed crate implementation, tests, and docs.md to reflect the new schema and event types.

Testing

• Ran formatting with just fmt and lint fixes with just fix -p nori-installed (ran automatically as part of the change process).
• Ran unit tests with cargo test -p nori-installed, and all tests passed (28 passed; 0 failed).
• Verified the updated behavior via the crate's unit tests for deterministic client id, upgrade detection, resurrection detection, state read/write, and analytics payload serialization (all test cases succeeded).

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Codex Task

[CSRessel]

Closing in favor of #226