PR #15895 BOLT-2193 — address CodeRabbit review on V2 shadow site-list

Pushed db2d145 to BOLT-2193/adapters-oem fixing 3 of 4 CodeRabbit threads: (1) atomic in-progress claim via cache.setIfAbsent for sites-list catalog listing, (2) 24h completion marker set only after successful store (store now returns bool), (3) config parseSolaredgeSitePollConcurrency rejects non-positive at boot. Declined thread #4 (distributed Redis minute-gate) as out-of-scope/against-spec; left open + cc Slava. All 9 sitesShadow tests pass, eslint clean, tsc clean (modulo pre-existing @types env noise). Next: monitor CI green + CodeRabbit re-review, do NOT merge.