Usage widgets permanently show 0% on Enterprise accounts; add an option to hide them when usage is zero

[tough-griff]

On Enterprise accounts the usage API returns null for every rate-limit window (see #343), which ccstatusline correctly reads as 0%. The session/weekly usage widgets are then permanently stuck at zero, and the session reset timer keeps counting down from transcript block metrics next to a usage figure that never moves:

$XYZ ▓▓▓▓▓▓▓▓▓░ 85.1% | 0% 2h5m | 0%

Widgets, left to right (raw-value mode):

Output	Widget	Hide states
$XYZ	Extra Usage Used	disabled,no-data
▓▓▓▓▓▓▓▓▓░ 85.1%	Extra Usage Utilization	disabled,no-data
0%	Session Usage	no-data
2h5m	Block Reset Timer	no-data
0%	Weekly Usage	no-data
(hidden)	Weekly Reset Timer	no-data

Widget config for this line

[
  {
    "id": "fb09dd02-a41b-4172-bfdf-4dd7e329b8a7",
    "type": "extra-usage-used",
    "color": "ansi256:11",
    "rawValue": true,
    "metadata": {
      "hide": "disabled,no-data"
    },
    "numberFormat": {
      "style": "compact"
    }
  },
  {
    "id": "9fdb44e0-25bf-44ac-b943-a34f1b377d18",
    "type": "separator",
    "character": " "
  },
  {
    "id": "351546ed-1c7c-4663-8c2a-cf7ca36443b7",
    "type": "extra-usage-utilization",
    "color": "ansi256:11",
    "numberFormat": {
      "style": "compact"
    },
    "rawValue": true,
    "metadata": {
      "display": "slider",
      "hide": "disabled,no-data",
      "invert": "false"
    }
  },
  {
    "id": "7b2987cb-1c37-4f4c-bce6-4adb6d482626",
    "type": "separator",
    "color": "ansi256:7",
    "dim": true
  },
  {
    "id": "b125133a-d2da-4254-955e-ad9bfa5a3487",
    "type": "session-usage",
    "color": "ansi256:80",
    "numberFormat": {
      "style": "compact"
    },
    "rawValue": true,
    "metadata": {
      "invert": "false",
      "display": "time",
      "hide": "no-data"
    }
  },
  {
    "id": "52245476-8615-43c9-8db5-7fd37c45139c",
    "type": "separator",
    "character": " "
  },
  {
    "id": "6fa9558a-8a03-442c-bfef-dfb5854cba65",
    "type": "reset-timer",
    "color": "ansi256:80",
    "dim": true,
    "numberFormat": {
      "style": "compact"
    },
    "rawValue": true,
    "metadata": {
      "display": "time",
      "compact": "true",
      "absolute": "false",
      "hide": "no-data"
    }
  },
  {
    "id": "d7a551fb-4953-44bd-8448-ecaecacf9668",
    "type": "separator",
    "color": "ansi256:7",
    "dim": true
  },
  {
    "id": "a73d2332-9fbb-48f9-abc5-02d4561157ca",
    "type": "weekly-usage",
    "color": "ansi256:81",
    "numberFormat": {
      "style": "compact"
    },
    "rawValue": true,
    "metadata": {
      "display": "time",
      "invert": "false",
      "hide": "no-data"
    }
  },
  {
    "id": "1df9ff5e-64a3-41ad-8f97-d45367ba35ee",
    "type": "separator",
    "character": " "
  },
  {
    "id": "1a69f9af-0275-40f5-8521-af07f0e8940b",
    "type": "weekly-reset-timer",
    "color": "ansi256:81",
    "dim": true,
    "numberFormat": {
      "style": "compact"
    },
    "rawValue": true,
    "metadata": {
      "display": "time",
      "compact": "true",
      "hours": "false",
      "hide": "no-data"
    }
  }
]

On this account extra usage is the only thing that moves. Session Usage, the Block Reset Timer and Weekly Usage never change, so they're pure noise, and no-data can't hide them because the data is present and reads 0%. (Weekly Reset Timer is only hidden because no weekly window is reported at all.) The same happens briefly on regular plans right after a window resets, and the per-model weekly widgets (Sonnet/Opus/Fable) and Extra Usage Used/Utilization sit at zero for most non-Enterprise users most of the time.

Proposal: add an opt-in zero hideable state (same as the one the git counters, token widgets and Compaction Counter already have) to:

• Session / Weekly / Weekly Sonnet / Weekly Opus / Weekly Fable Usage: hide while usage is 0%
• Block Reset Timer / Weekly Reset Timer: hide while that period's usage is 0% and no reset window has started
• Extra Usage Used / Extra Usage Utilization: hide while nothing has been spent

Extra Usage Remaining would not get it. Hiding it at zero spend hides the full budget, and hiding it at $0 left hides the one warning worth showing.