[AZ-810] Clamp UAV test-fixture coordinates to OSM-valid range

The AZ-810 metadata validator rejects lat outside [-90, 90] and lon
outside [-180, 180]. Two NextTestCoordinate() helpers seeded their
counter from `(Ticks/TicksPerSecond) % 1_000_000` and returned
`60 + n*0.0005`, producing lat well above 90° for almost any seed
(e.g. n=200000 -> lat=160). Pre-AZ-810 there was no validator and no
DB constraint, so the out-of-range values were silently accepted; the
new validator (correctly) rejected them at HTTP 400.

Clamp both helpers to non-overlapping OSM-valid ranges:
  - UavUploadTests.cs:           lat in [50, 70),  lon in [10, 40)
  - UavUploadValidationTests.cs: lat in [-70, -50), lon in [-40, -10)

Non-overlap (not the prior +5_000_000 counter offset) is what now
guarantees AZ-488 and AZ-810 suites don't collide on the per-source
UNIQUE index when both run against the same DB.

No production code change; AZ-810 validator behaviour is unchanged.

Also:
- Correct AC-9 in batch_04_cycle8_report.md: the original claim
  ("verified by tracing source") was a false-PASS; the autodev
  Step 11 test run surfaced the gap. Now confirmed by full-suite
  green (scripts/run-tests.sh --full).
- Add ring-buffer lesson on AC-verification standards for input-
  validation changes: tracing fixture variables to their generators
  is insufficient; only a green integration-test run is sound
  evidence for a "no-regression" AC.

Co-authored-by: Cursor <cursoragent@cursor.com>

_docs/LESSONS.md

@@ -37,6 +37,8 @@ If the enum's wire string happens to match a member name case-insensitively (e.g
 
 ## Ring buffer (last 15 entries — newest at top)
 
+- [2026-05-23] [process] When verifying a "no-regression" AC for an input-validation change ("AZ-NNN does not break existing tests"), the only sound evidence is a green integration-test run — tracing fixture variables back to their generators in source is insufficient because helpers can produce values outside the new bounds and previously slipped through silently when no validator existed; document the standard as "verified by reading source" → unconfirmed, "verified by full test run" → confirmed, and gate the batch report's AC table on the latter before the implement skill closes the batch (cycle 8: AZ-810 batch_04 AC-9 claimed "no AZ-488 regression" based on tracing `latitude = coord.Latitude` in test source, but `NextTestCoordinate` seeded by `(Ticks/TicksPerSecond) % 1_000_000` produced lat far above 90° at runtime; the false-PASS only surfaced at autodev Step 11 when the integration test run returned HTTP 400 from the new validator on the AZ-488 happy path).
+  Source: _docs/03_implementation/batch_04_cycle8_report.md (AC-9 row)
 - [2026-05-22] [process] When the implement skill ships a cycle's batch commit without writing `_docs/03_implementation/implementation_report_*_cycle{N}.md`, downstream skills (test-spec cycle-update, document task mode, retrospective Step 1) must fall back to reading the cycle's task specs in `_docs/02_tasks/done/` plus the commit body via `git log --grep='[AZ-...]'` — codify the fallback in those skills' instructions instead of leaving it as per-cycle improvisation, because the implicit contract between Step 10 and Steps 11-17 broke silently this cycle and only succeeded because every downstream skill happened to be robust enough to substitute (cycle 7: AZ-794+AZ-795+AZ-796 shipped as commit `865dfdb` with no report artifact; doc-skill auto-walked the diff, test-spec read the task specs, retrospective wrote from the deploy + security + perf reports — all worked, but the contract was never formal).
   Source: _docs/06_metrics/retro_2026-05-22_cycle7.md
 - [2026-05-22] [testing] When a strict-validation layer ships (`JsonSerializerOptions.UnmappedMemberHandling.Disallow`, FluentValidation rules, explicit DTO `[JsonRequired]`), expect the project's own integration tests to surface latent bugs the prior lenient defaults had been masking — silent PascalCase fallback property names, out-of-range fixture coordinates, wrong-cased JSON keys; correct them in the same PR or the test suite goes red and the strict layer looks like a regression instead of the bug-finder it is (cycle 7: `IdempotentPostTests.RoutePoint` had been posting `{"Lat":...}` against a `[JsonPropertyName("lat")]` DTO for months; the new strict deserializer caught it and the 2-line payload fix landed alongside the strict layer).