Fix a self-contradicting microSD spec and a dead Rockchip wiki link

[munzzyy]

Two unrelated accuracy fixes I hit while reading through the hardware pages.

microSD spec contradicts itself inside one file. Tech-Specs.md states the slot spec twice. Under Ports it's asserted flat out, under Memory and storage it carries the "needs verification" warning:

• line 66: - **MicroSD card slot:** supports UHS-I SDR104
• line 109: - **MicroSD card slot:** ⚠️ (UHS-I SDR104 — needs verification)

No other page mentions microSD, so there's nothing to break the tie. I matched line 66 to the cautious version rather than the confident one, since dropping a caveat needs evidence it's been resolved and I don't have that. If the slot has since been verified, the fix is the other direction and I'm happy to flip it.

Dead Rockchip wiki link. RK3576-Boot-flow.md links to opensource.rock-chips.com/wiki_Boot_option. That domain doesn't resolve any more — it CNAMEs to opensource.rock-chips.com.qtlgslb.com., which returns NXDOMAIN from both Cloudflare and Google DoH, so it's the zone being gone rather than one resolver being unhappy. There's no Wayback snapshot to point at either.

The sentence is still worth keeping, since it's warning people off the obsolete miniloader/idbloader terminology, so I left the text and just removed the link.

One thing I couldn't settle, flagging rather than guessing: Power-subsystem.md:21 says the battery is 22.9 Wh and Tech-Specs.md:115 says 24000 mWh. Same 2-cell pack. I can't tell which is canonical from the repo alone, so I left both alone — happy to send a follow-up once someone confirms the real number.