[HalfSweet]

An SLogic's rate tiers are its wire modes, chosen by the highest enabled channel. The acquisition menu named them by their range of channels: "0–3", "0–7", "0–15", "0–31". A faster rate in the sample-rate list that needs one of them was marked "0–7 only", which doesn't read as the name of anything. Sipeed's own documentation names these modes by their width: 4, 8, 16 and 32 ch.

• RateTier gains named_by_count, which only the SLogic driver sets. The acquisition menu names such a tier by its channel count: "8 ch" (Chinese: 「8 通道」) over its rate in the tier row, and the same "8 ch" next to a rate that needs it. There is no "≤", because that tier does not accept any 8 channels.
• The tooltips still say which channels a tier takes ("Channels 0–7, up to 400 MHz"), and the caption about a high channel forcing a wider tier is unchanged.
• PXLogic's and DSLogic's tiers of the first channels keep their range names. Tiers that take any N channels are still named "N ch", with "≤N ch" in the rate list.
• The ?mocktiers=1 mock's Stream tiers, modelled on an SLogic16U3, now go by their count as well.
• DESIGN.md §4 and the user guide describe the new names.

Validation:

• pnpm exec eslint src, pnpm typecheck, Prettier on the changed files
• pnpm test: 86 files, 610 tests passed. A new case in AcquisitionMenu.test.ts checks the tier row, the rate-list note and the tooltips for tiers named by count; the existing cases still cover range-named tiers.
• cargo clippy --workspace --all-targets -- -D warnings; cargo test for hsync-driver, hsync-slogic, hsync-dslogic, hsync-pxlogic, hsync-atklogic and hsync-session: 280 passed. The SLogic tier test asserts the new flag.
• Checked the acquisition popover with ?mocktiers=1 in headless Chrome at 1440×900 in Light and Dark, Comfortable and Compact, in Chinese and English: the tier row reads 4 / 8 / 16 通道 (ch), and greyed rates read "8 通道" / "4 通道" (ch) without crowding.