feat: Usage & Spend tab, external hooks, Cursor cost labels (0.44/0.45 deferred)

[Finesssee]

Summary

Ports deferred upstream 0.44/0.45 UI pieces to Win-CodexBar:

1. Usage & Spend settings tab (upstream 0.44 steipete#2116)

• New usageSpend settings tab with provider | 7d | 30d | currency table
• Tauri command get_usage_spend_summary using CostScanner for Codex/Claude local logs
• Includes period cost snapshots from cached providers when available
• No share-card PNG (P2 skip)

2. External hooks (upstream steipete#2001) — minimal but real

• rust/src/core/hooks.rs: HookEvent, HookRule, HooksConfig, HookRunner, HookRateLimiter
• Loads %APPDATA%\CodexBar\hooks.json (next to settings)
• Spawn binary with no shell; env whitelist PATH/HOME/USER/TEMP (+ TMP/USERPROFILE) + CODEXBAR_*
• Stdin JSON payload ≤4KiB; timeout; in-process rate limiter for spammy events
• Wired on provider refresh when high/critical/exhausted/reset thresholds are crossed
• Settings Advanced tab: enable toggle hooks_enabled + path help text
• Unit tests for payload/env + rate limiter

3. Cursor token-cost deepen (best-effort)

• Plan usage still clamps ≤100 (already)
• Clearer CostSnapshot period labels: On-demand (billing cycle) and Plan (since …) from existing usage-summary fields only (no new network endpoints)

Tests

cargo test --manifest-path rust/Cargo.toml hooks
cargo test --manifest-path rust/Cargo.toml plan_cost_period
cargo test --manifest-path rust/Cargo.toml test_cursor_on_demand
cargo check --manifest-path apps/desktop-tauri/src-tauri/Cargo.toml
node apps/desktop-tauri/scripts/check-locale-drift.mjs  # OK 691 keys

Note: core::provider::tests::test_provider_id_all fails pre-existing (63 vs 59 count from earlier provider ports); unrelated to this change.

Example hooks.json

{
  enabled: true,
  events: [
    {
      enabled: true,
      event: quota_low,
      threshold: 0.7,
      executable: C:\\\\path\\\\to\\\\notify.exe,
      arguments: [],
      timeoutSecs: 10
    }
  ]
}

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