Let nukes fly over impassable terrain

[evanpelle]

Description:

Nukes (and MIRVs) now fly over impassable terrain instead of being blocked by it. This removes the trajectory restriction introduced with impassable terrain in #4340 and supersedes the silo path-selection workaround from #4815.

Core (sim):

• NukeExecution no longer aborts the launch or flips the curve direction when the parabola crosses impassable terrain
• PlayerImpl.nukeSpawn picks the plain closest ready silo again; the MIRV special case collapsed away since nothing is blocked anymore
• Nation AI (NationNukeBehavior) no longer skips silos/targets whose trajectory crosses impassable terrain
• Deleted the now-unused isParabolaBlocked / clearParabolaDirection helpers from PathFinder.Parabola.ts

Unchanged — impassable terrain itself still can't be nuked:

• Targeting an impassable tile is still rejected in nukeSpawn
• The blast radius still skips impassable tiles (no destruction / flooding)

Client preview:

• Hovering impassable terrain with a nuke selected keeps the ghost icon and blast circle hidden (the "void" treatment from Add impassable terrain 🗺️ #4340), but now shows the trajectory arc with the red X marker pinned at the untargetable destination. This reuses the existing SAM-intercept marker machinery by clamping tSamIntercept to 0.9999 — the X tracks the live cursor per frame
• Removed the impassable-blocked (red arc + mid-flight X) preview logic and the silo/curve mirroring of the old sim behavior

Tests: trajectory tests rewritten to assert fly-over-and-detonate; curve-flip and blocked-silo-selection tests from #4815 removed; NukeTrajectory.test.ts trimmed to the generic threshold math.

🤖 Generated with Claude Code

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: c3b0bd9b-e505-4670-a09d-318e72803d25

📥 Commits

Reviewing files that changed from the base of the PR and between af154a0 and 9f01b9d.

📒 Files selected for processing (8)

• src/client/controllers/BuildPreviewController.ts
• src/client/render/gl/utils/NukeTrajectory.ts
• src/core/execution/NukeExecution.ts
• src/core/execution/nation/NationNukeBehavior.ts
• src/core/game/PlayerImpl.ts
• src/core/pathfinding/PathFinder.Parabola.ts
• tests/ImpassableTerrain.test.ts
• tests/NukeTrajectory.test.ts

💤 Files with no reviewable changes (1)

• src/core/pathfinding/PathFinder.Parabola.ts

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Walkthrough

Nuke trajectories no longer treat impassable terrain as a launch or path blocker. Preview rendering still marks blocked destinations, while ghost validation remains separate. Silo selection, AI planning, execution, and tests now support terrain-crossing nukes.

Changes

Nuke terrain crossing behavior

Layer / File(s)	Summary
Trajectory thresholds src/client/render/gl/utils/NukeTrajectory.ts, tests/NukeTrajectory.test.ts	Removed terrain interception from threshold computation. SAM and untargetable-zone handling remain covered by tests.
Build preview flow src/client/controllers/BuildPreviewController.ts	Trajectories render over impassable destinations. Invalid build ghosts remain suppressed, and blocked destinations receive an X marker.
Launch and silo selection src/core/execution/NukeExecution.ts, src/core/execution/nation/NationNukeBehavior.ts, src/core/game/PlayerImpl.ts, src/core/pathfinding/PathFinder.Parabola.ts	Removed terrain-clearance checks and parabola-direction switching. Silo selection now uses the nearest eligible silo.
Behavior tests tests/ImpassableTerrain.test.ts	Updated terrain fixtures and tests for active terrain-crossing nukes and terrain-independent silo selection.

Estimated code review effort: 4 (Complex) | ~45 minutes

Possibly related PRs

• openfrontio/OpenFrontIO#4756: Both change impassable-terrain handling in NukeExecution.ts.
• openfrontio/OpenFrontIO#4815: Directly concerns the same terrain validation and clearParabolaDirection logic.
• openfrontio/OpenFrontIO#4235: Both modify nuke trajectory preview handling in BuildPreviewController.ts.

Suggested labels: Bugfix

Suggested reviewers: aotumuri

Poem

Across the wall, the nuke flies,
SAMs still watch the open skies.
The nearest silo takes its stand,
While ghosts stay off forbidden land.
A marked X guards the ground below.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: nukes can cross impassable terrain.
Description check	✅ Passed	The description accurately covers simulation, AI, client preview, targeting, blast effects, and test changes related to the pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Create stacked PR
• Commit on current branch

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