ui/phase-13: planet inspector — read-only

Plumbs the map → inspector pathway: a click on a planet selects it
through the new SelectionStore, the sidebar Inspector tab swaps
its empty-state copy for a per-kind read-only field set, and a
mobile-only bottom-sheet mirrors the same content over the map.
Field projection in api/game-state.ts now surfaces every documented
planet field.

ui/docs/navigation.md

@@ -48,13 +48,18 @@ The desktop sidebar hosts three tools:
 | Inspector  | `lib/sidebar/inspector-tab.svelte`     | Phase 13 / 19        |
 | Order      | `lib/sidebar/order-tab.svelte`         | Phase 12 / 14        |
 
-The sidebar's selected-tab state is a `$state` rune inside
-`lib/sidebar/sidebar.svelte`. The component is mounted by the layout
-at `routes/games/[id]/+layout.svelte`, and SvelteKit keeps that
-layout instance alive while the user navigates between child routes
-(`/games/:id/map` → `/games/:id/report` → …). The rune therefore
-survives every active-view switch automatically, with no URL coupling
-needed.
+The selected-tab state is a `$state` rune in
+`routes/games/[id]/+layout.svelte`, bound into
+`lib/sidebar/sidebar.svelte` via `$bindable()`. The layout owns the
+rune so external events — Phase 13's planet click, future similar
+flows — can drive the active tab from outside the sidebar without
+plumbing callbacks. The component is mounted by the layout, and
+SvelteKit keeps that layout instance alive while the user navigates
+between child routes (`/games/:id/map` → `/games/:id/report` → …),
+so the rune survives every active-view switch automatically with no
+URL coupling needed. The URL seed and the history-mode reset
+described below still live inside the sidebar — they mutate the
+bindable in place; the layout sees the change through the binding.
 
 A `?sidebar=calc|calculator|inspector|order` URL param is read once
 on mount and seeds the initial tab. Later phases that want to land
@@ -95,9 +100,9 @@ Three discrete CSS modes matched to the IA section diagrams:
   view-menu trigger swaps to a hamburger icon (☰) that opens the
   drop-down as a full-width drawer below the header.
 
-Inspector is intentionally unreachable on mobile in Phase 10. Per the
-IA section the mobile inspector is a bottom-sheet raised by tapping a
-map object, and that mechanism waits for Phase 13.
+On mobile the bottom tab row does not include `Inspector`. The
+inspector content is reached by tapping a map object instead, which
+raises a bottom-sheet — see [Planet selection](#planet-selection-phase-13).
 
 ## Mobile bottom-tabs and tool overlay
 
@@ -132,6 +137,62 @@ back-stack mechanism. Phase 34 lands the back-stack alongside its
 first user (multi-turn projection, range circles in the ship-class
 designer).
 
+## Planet selection (Phase 13)
+
+The map view turns into the entry point for the inspector by
+translating a renderer click into a planet selection. The flow:
+
+1. The renderer (`src/map/render.ts`) exposes `onClick(cb)` next to
+   the existing `hitAt(cursor)`. It is built on `pixi-viewport`'s
+   `clicked` event, which already differentiates a click from a
+   pan-drag, so a click handler will not race the pan plugin.
+2. `lib/active-view/map.svelte` wires that callback after a successful
+   `mountRenderer`. On a click it asks the renderer for the hit
+   primitive, looks the planet up by `number` in the live
+   `GameStateStore.report`, and calls `SelectionStore.selectPlanet(number)`.
+3. `SelectionStore` (`lib/selection.svelte.ts`) is a runes store
+   instantiated by the layout and exposed via Svelte context under
+   `SELECTION_CONTEXT_KEY`. It carries a discriminated union — Phase
+   13 only models `{ kind: "planet"; id: number }`; Phase 19 widens
+   it for ship groups. Selection is in-memory only: it survives the
+   layout's lifetime (active-view switches inside `/games/:id/*`)
+   but does not persist across reloads — that contrast with the
+   order draft is intentional.
+4. The layout watches the selection rune and, on the null → planet
+   transition, flips its bound `activeTab` to `inspector` and
+   `sidebarOpen` to `true`. Desktop already has the sidebar pinned;
+   tablet needs the drawer to surface; mobile is unaffected by the
+   tab rune because the sidebar is CSS-hidden there.
+5. `lib/sidebar/inspector-tab.svelte` and
+   `lib/inspectors/planet-sheet.svelte` both read the selection
+   store, resolve it against the live report, and either render
+   `lib/inspectors/planet.svelte` or fall back to the empty state.
+   A selection that points at a planet missing from the current
+   report (visibility lost between turns) collapses to the empty
+   state instead of holding stale rows.
+
+The mobile bottom-sheet is mounted alongside `<BottomTabs />` in the
+layout. Its visibility is conditional on `effectiveTool === "map"` so
+it does not stack on top of the calc / order overlays. Phase 13 ships
+the minimal dismissal surface: a close button (`✕`) that calls
+`SelectionStore.clear()`. Tap-outside and swipe-down dismissal from
+the IA section are deferred to Phase 35 polish. A click that lands on
+empty space is a no-op — selection is mutated only by an explicit
+planet click or by the close button.
+
+The planet inspector itself is a presentational component: it takes
+a `ReportPlanet` snapshot as a prop and renders the documented field
+set per planet kind. The wrapper in `api/game-state.ts` exposes every
+field the FBS schema carries (`industryStockpile` for `capital`,
+`materialsStockpile` for `material`, `industry`, `population`,
+`colonists`, `production`, `freeIndustry`, plus `owner` for `other`).
+Fields the FBS table does not project for a given kind read as `null`
+and the inspector simply omits the row.
+
+The selected-planet visual on the map (a ring or halo) is **not**
+shipped in Phase 13. It rolls into Phase 35 polish together with the
+sheet's swipe-to-dismiss gesture.
+
 ## Auth gate
 
 The root `+layout.svelte` redirects `anonymous → /login` for any