docs: Mark full air-gap build as VERIFIED

Complete build test successful:
- 4098/4098 tasks succeeded
- TMPDIR on /srv/yocto/tmp (63GB volume)
- EULA fix: ACCEPT_FSL_EULA = "1" in local.conf
- Output: tq-image-small-debug + device trees
- Build time: ~3.5 hours (2 parallel jobs, 8GB RAM)

docs/02-mirror-creation/step-by-step-mirror-creation.md

@@ -286,7 +286,7 @@ bitbake tq-image-small-debug
 | Debian 13 host | ✅ | Warning but functional |
 | Ubuntu 22.04 host | ✅ | Tested in Docker, all steps pass |
 | Air-gapped fetch (BB_NO_NETWORK=1) | ✅ | 510/510 from local mirror |
-| Full build | ⬜ | Not tested (sandbox RAM limit, needs 8GB+) |
+| Full build | ✅ | Air-gap verified 2026-03-02 (4098/4098 tasks) |
 
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