feat(ui): Phase 30 ship-class calculator with goal-seek and reach circles

Fuse the standalone ship-class designer (Phases 17/18) into a sidebar calculator: live mass/speed/attack/defence/bombing results, a planet build-rate readout, single-target goal-seek, a modernization-cost mode, and auto reach circles on the map for the selected planet.

pkg/calc becomes the single source for the new math (no mirroring): extract BombingPower from the engine model and the per-turn ship-production loop from controller.ProduceShip into pkg/calc (engine now delegates), and add inverse goal-seek solvers in pkg/calc/solve.go. Thin-bridge the combat, planet-build, and solver functions through ui/core/calc + ui/wasm and rebuild core.wasm.

Remove the standalone designer view/route; the ship-classes table and the view/bottom menus open the calculator via a shared request store.

Docs: rewrite ui/PLAN.md Phase 30, adjust Phase 34 (realistic forecast + CAP/COL ownership), add ui/docs/calculator-ux.md, extend calc-bridge.md, fix navigation.md; remove ui/CALCULATOR.md.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/docs/navigation.md

@@ -27,16 +27,17 @@ separate dispatch component.
 | `/games/:id/report`                        | `lib/active-view/report.svelte` (see [report-view.md](report-view.md)) | Phase 23 |
 | `/games/:id/battle/:battleId?`             | `lib/active-view/battle.svelte`                | Phase 27                |
 | `/games/:id/mail`                          | `lib/active-view/mail.svelte`                  | Phase 28                |
-| `/games/:id/designer/ship-class/:classId?` | `lib/active-view/designer-ship-class.svelte`   | Phase 17 (CRUD) / 18 (calc preview) |
 | `/games/:id/designer/science/:scienceId?`  | `lib/active-view/designer-science.svelte`      | Phase 21                |
 
 `/games/:id` (no trailing view) redirects to `/games/:id/map`. The
-optional `:classId?` / `:scienceId?` segments on the designer
-routes match SvelteKit's `[[classId]]` syntax — `/designer/ship-class`
-opens the empty new-class form, `/designer/ship-class/{name}`
-opens the read-only view of the named class with the Delete
-affordance. Phase 17 lights up the ship-class CRUD path; Phase 18
-adds the live `pkg/calc/`-backed preview pane on top.
+optional `:scienceId?` segment on the science designer route matches
+SvelteKit's `[[scienceId]]` syntax — `/designer/science` opens the
+empty new-science form, `/designer/science/{name}` opens the named
+science. Phase 17/18 originally added a parallel ship-class designer
+route; Phase 30 removed it and folded ship-class design into the
+sidebar ship-class calculator (`lib/sidebar/calculator-tab.svelte`,
+see [calculator-ux.md](calculator-ux.md)), reached from the
+ship-classes table and the view/bottom menus.
 
 The `entity` slug on the table route is kebab-case (`planets`,
 `ship-classes`, `ship-groups`, `fleets`, `sciences`, `races`).
@@ -163,10 +164,11 @@ Tables, History, Settings, Logout) is the polish target for Phase 35
 ## Transient map overlays
 
 Some views can push a transient overlay onto `/map` with a back
-affordance — for example, the ship-class designer pushes a
-range-preview overlay onto the map. The transient overlay clears
-when the user navigates to any other view via the header or the
-bottom-tabs.
+affordance. (Phase 30's calculator reach circles are a simpler,
+always-on map extra rather than a back-stacked overlay; the transient
+back-stack mechanism itself is still a Phase 34 concept.) A transient
+overlay clears when the user navigates to any other view via the header
+or the bottom-tabs.
 
 Phase 10 documents this concept but does not implement the
 back-stack mechanism. Phase 34 lands the back-stack alongside its