Improve small-terrain placement and show startup failure causes; record Workshop 0.0.120

docs/terrain-takeover.md

@@ -124,8 +124,32 @@ candidate still passes terrain, navigation, slope and aircraft-clearance checks;
 a missing airport does not allow an unsafe spawn. Searches have finite time and
 attempt budgets and never fall back to coordinates from another map.
 
+Terrain-generated placement allows up to 48,000 candidates or 120 seconds per
+site, whichever comes first, keeping the existing cooperative 8 ms work slices.
+Airport-only extraction searches broaden after 12,000 candidates or 30 seconds
+without resetting that total budget. The fallback surveys the terrain for a
+helicopter landing zone and retains the normal primary/secondary aircraft
+clearance and navigation checks.
+
+On terrain-generated maps, prison-to-airport separation is 15% of the shorter
+world axis, clamped to 200–1,500 m (300 m on a 2 km map). This changes tactical
+spacing, not the physical footprint or slope allowance. Original authored Everon
+placement retains its 1,500 m airport buffer and existing search/fallback rules.
+Maps without sufficient clear ground or a working Soldiers navigation mesh can
+still fail preparation. See [placement validation](evidence/small-terrain-placement-2026-10-24/README.md).
+
+Search diagnostics use the `Reintroduced [placement search]` log prefix. Each
+summary identifies the site, attempts and elapsed milliseconds, with counts for
+failed or deferred checks: water, uneven ground, obstacles, road/airport distance,
+site spacing, navigation and aircraft clearance. Summaries appear on completion,
+exhaustion and airport fallback, plus every 30 seconds during a long search.
+Counts describe checks rather than unique candidates: a candidate awaiting a
+navigation tile can be checked repeatedly. Mandatory placement failures also
+include the site and rejection summary directly on the loading screen, so no
+chat command is needed. The same detail remains available in mission status.
+
 The selected scenario must supply `SCR_BaseGameMode`, a usable `Soldiers` navmesh,
-world bounds spanning 2–100 km on both axes, and enough clear navigable ground.
+world bounds spanning 1–100 km on both axes, and enough clear navigable ground.
 Navigation remains the terrain author's responsibility. A plain exploration
 scenario is the recommended starting point. Arbitrary scripted scenarios can
 retain their own tasks and entities; saved campaigns and every third-party game