fix(data): un-pair 7 genuinely different smartphone devices

[Seungpyo1007]

Summary

A focused pass for one specific pattern the earlier brand-prefix dedup (#329 / #330
/ #334) kept surfacing: pairs flagged as duplicates that are actually two
different products sharing a base name, which the mechanical slug-matching
couldn't distinguish. This finds 7 (the 3 previously reported plus 4 new) and
un-pairs them — no merges.

Each was confirmed against a source as a genuinely distinct device, then un-paired
by giving the mis-slugged variant a distinct slug / filename / name so it no longer
collides with the base model:

base slug (was)	variant → new slug	why distinct (source)
u11	HTC U11+ → u11-plus	separate fall-2017 model, smaller bezels (androidcentral)
one-m9	HTC One M9+ → one-m9-plus	Helio X10 + QHD, separate from SD810 One M9
p40-pro	Huawei P40 Pro+ → p40-pro-plus	distinct higher model (pocket-lint, CNET)
xperia-z3	Sony Xperia Z3+ → xperia-z3-plus	= Xperia Z4, distinct 2015 SD810 model, own Wikipedia page
razr	Motorola Razr (2023) → razr-2023	different generation from the 2019 Razr
fairphone-3-dual-sim-lte-fp3	Fairphone 3+ → fairphone-3-plus-dual-sim-lte-fp3plus	2020 successor to the 2019 Fairphone 3
gigabyte-gsmart-gs202	GSmart GS202+ → gsmart-gs202-plus	distinct "+" variant

In each pair the other record (the base model — htc-u11, htc-one-m9,
huawei-p40-pro, sony-xperia-z3, motorola-razr, and the base Fairphone 3 /
GS202) is left untouched. Nothing merged, nothing invented — only slug,
base_model_slug, name and filename change on the renamed side so the two devices
stop colliding as a false pair. New slugs are collision-free.

Counts

• confirmed-different-devices, un-paired: 7
• resolved-and-merged: 0 (this pass is only for the different-device pattern)
• Residual brand-prefix pairs drop from 183 to 176. The rest of the residual (21
  same-model wrong-soc + 157 needing a per-record ram/weight/battery source) genuinely
  needs external sources I don't have and is deliberately left alone, per the task.

Validation

• python -m app.validate → passed.
• integrity_check.py <data> --strict → no hard anomalies (slug==filename holds
  for all renames; no duplicate slugs).
• 92,824 smartphone files (unchanged — these are renames, not deletions). Dump
  refreshed in the last commit (old base-name slug pages replaced by the new variant
  slugs).

Refs #296