data: initial RSS feed content fetch for newly added feeds

[514sid]

What

Initial RSS content fetch for the feeds discovered in the previous PR, so the newly added products start appearing in Industry News right away instead of waiting for the daily cron.

• Fetched all 254 product feeds plus the two industry feeds.
• 123 product feeds returned content; the other 130 were empty, dead, or blocked at fetch time (the daily cron will keep retrying them).
• 25 new feed cache files created; 125 cache files updated in total.

For this one-off backfill the per-feed item cap was temporarily raised so each feed's recent history was captured; the command itself is unchanged (still 10 per run for the daily cron).

Validation

hugo --minify builds clean.