docs(usage-tracking): refresh the overview screenshot and correct two stale facts (#7203)

The screenshot predates the source-mix radar and still shows the allowance pills
this branch removes. Replaced, with the declared height following the new aspect
ratio and alt text describing what is actually on screen.

Two things beside it had gone stale with the same release. The tab table listed
BYOK, which is withheld until the ledger carries rows for it, so the table
advertised a tab nobody can see; the section further down described that tab's
contents as though it were reachable. Both now state the billing behaviour, which
is unchanged and still worth documenting, without claiming a surface that is not
there. And "Open logs" no longer goes to the workspace's execution logs — it opens
the organization audit feed scoped to that workspace.

apps/docs/content/docs/en/platform/enterprise/usage-tracking.mdx

@@ -17,7 +17,7 @@ All figures are in **credits** (1 credit = $0.005). See [cost calculation](/plat
 
 Go to **Settings → Organization → Usage tracking** in your workspace.
 
-<Image src="/static/enterprise/usage-tracking-overview.png" alt="Usage tracking Overview tab showing the period selector, credits used against the organization limit, a daily usage chart, and a Sources breakdown listing Sim Chat, Workflow, and Agent block" width={900} height={578} />
+<Image src="/static/enterprise/usage-tracking-overview.png" alt="Usage tracking Overview tab showing the period selector, credits used against the organization limit, a daily usage chart, and a Sources section pairing a ranked list of sources with a radar chart of the same mix" width={900} height={781} />
 
 The period selector applies to every tab:
 
@@ -40,9 +40,8 @@ The period selector applies to every tab:
 | **Members** | Which people are driving usage |
 | **Workspaces** | Which workspaces are driving usage — select one to drill in |
 | **Models** | Which models we are paying for |
-| **BYOK** | What ran on our own provider keys |
 
-Selecting a workspace opens its detail view, which splits that workspace's usage into **Sources** (what kind of work) and **Workflows** (the individual workflow runs). **Open logs** jumps to that workspace's execution logs.
+Selecting a workspace opens its detail view, which splits that workspace's usage into **Sources** (what kind of work) and **Workflows** (the individual workflow runs). **Open logs** jumps to [audit logs](/platform/enterprise/audit-logs) filtered to that workspace.
 
 <Image src="/static/enterprise/usage-tracking-workspace-detail.png" alt="A workspace's detail view with a Sources section listing Sim Chat and Workflow, and a Workflows section ranking individual workflows by credits" width={900} height={598} />
 
@@ -90,12 +89,10 @@ These follow from how charges are recorded, and they explain most questions abou
 
 ## Bring your own keys (BYOK)
 
-When a workspace or organization supplies its own provider key, Sim does not charge for that model usage. Those calls are still recorded so you can see the volume.
-
-The **BYOK** tab groups this usage by provider and reports **tokens** rather than credits, because the credit cost is zero by definition. Tokens on your own keys are not included in the credit totals anywhere else in the panel.
+When a workspace or organization supplies its own provider key, Sim does not charge for that model usage. Those calls are still recorded, measured in **tokens** rather than credits — the credit cost is zero by definition — and they are not included in the credit totals anywhere in the panel.
 
 <Callout type="info">
-  Tool calls and Chat usage made on your own keys are not yet recorded. BYOK currently covers model usage in workflow runs.
+  This usage is not broken out in the panel today. Of what is recorded, only model usage in workflow runs is covered: tool calls and Chat usage made on your own keys are not recorded at all.
 </Callout>
 
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