Move API token creation to shared header, expand docs, update README (v0.16.19)

ROADMAP.md

@@ -162,3 +162,5 @@ Roughly in priority order:
 `v0.16.17` fixes the Backup type helper text showing both the Complete and Configuration-only explanations stacked on top of each other on page load or refresh, instead of just the one matching the currently selected option. Root cause: the help text only ever updated on the select's `change` event -- but `renderBackups()` sets the select's value from saved settings on every render without firing a `change` event, so the static placeholder text (which briefly held both sentences as a v0.16.16 authoring mistake) never got replaced until you manually touched the dropdown. Factored the text-selection logic into its own function and call it both on `change` and every time `renderBackups()` runs, so it always matches the select's actual current value.
 
 `v0.16.18` reworks the API Access tab to match the Users and Groups tabs' layout instead of the old plain data-row list: tokens are now shown as tiles in the same card grid Hosted Sites/Users/Groups use, and a stat bar above them breaks down Active/Revoked and Full access/Read-only counts at a glance. No behavior changed -- Revoke still works the same way it always has (a one-way action; there is no re-enable, since a revoked token's secret is treated as compromised). An earlier idea of adding an enable/disable toggle was dropped once it became clear that would require adding real token-reactivation support on the backend, a deliberate security-posture change rather than a layout fix.
+
+`v0.16.19` finishes the API Access tab's alignment with Users and Groups: the "Create token" button now lives in the shared top-right header button used by every other create action instead of its own row inside the panel, and the panel-heading text ("Programmatic access / API access tokens / Issue bearer tokens...") has been removed the same way it was for Groups in v0.16.15, since the tab button's own label already says what the section is -- the stat bar is now the first thing in the panel. Also walked the in-app Documentation view and brought it current with everything shipped since it was last substantively updated: added a full API Access section (creating a token, scope, expiry, the one-time reveal, revoking, and automatic revocation when an issuing administrator's password changes or account is disabled), corrected the Performance section's per-route table description to drop the removed per-row error-count badge and instead document the pinned column headers and the "Not configured" chip added in v0.16.16, and added an API Access entry to the documentation sidebar's contents list.