Taller popup so more AI providers are visible at once without scrolling. Tightened the extension's site access to TensorFeed API endpoints only (previously the full tensorfeed.ai site). No new permissions and no data collection.

Taller popup on Firefox: roughly three more AI provider rows now fit on screen at once without scrolling. Also tightened the header text so the "no data" count is never truncated.

Single user-facing fix: the popup was 520px wide and cut off the widget's
header text and last filter tab. Bumped to 760x600 (Chrome's popup ceiling
is 800x600, leaving a 40px right gutter) so the full header
("CONDITION GREEN, ALL MONITORS, hh:mm:ss TZ") and all six filter chips
fit without ellipsis. At 760px the widget also clears its own 720
breakpoint and shows the Detail column alongside the sparkline.

Files changed:
- extension/popup.html (4 width values: 520 -> 760, plus iframe height
560 -> 600, plus updated comment)
- extension/manifest.json (version 1.0.2 -> 1.0.3; everything else
identical to the 1.0.2 baseline)

No permission changes. No host_permissions changes. No new APIs touched.