docs(ui): finalize MVP plan structure and de-archaeologize topic docs

MVP web client (Phases 1-30) is complete; reorganize planning + living docs around that.

- PLAN.md kept as the staged MVP record (1-30) with a status block + pointers; removed the 31-36 stages, regression scenarios, and deferred-TODO section (moved out); fixed a stale cross-machine plan path.

- ui/PLAN-finalize.md (new): active web-finalization plan in 8 stages (visual system, a11y, i18n, error UX, PWA, build hygiene, docs, owner manual-QA loop); absorbs former Phases 33 and 35.

- ui/ROADMAP.md (new): post-MVP (Wails, Capacitor, realistic projection, acceptance + regression scenarios) and triaged deferred follow-ups.

- ui/docs/README.md (new): grouped topic-doc index.

- De-archaeologized all 20 ui/docs topic docs + ui/README.md + ui/core/README.md: stripped Phase-N build history, rewritten as current-state; deferred work now points at ROADMAP.md / PLAN-finalize.md. Docs-only; no code change.

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

ui/docs/ship-group-actions.md

@@ -1,7 +1,7 @@
 # Ship-group inspector actions
 
-Phase 20 turns the read-only ship-group inspector
-(`ui/frontend/src/lib/inspectors/ship-group.svelte`) into an
+The ship-group inspector
+(`ui/frontend/src/lib/inspectors/ship-group.svelte`) is an
 interactive command source for the player's own groups in orbit.
 This document is the running spec for the actions panel
 (`ui/frontend/src/lib/inspectors/ship-group/actions.svelte`):
@@ -151,9 +151,8 @@ count. Block masses come from the player's
 - Drive / shields / cargo block mass = the corresponding ship-
   class field (raw value).
 - Weapons block mass = `core.weaponsBlockMass({ weapons,
-  armament })` (Phase 18 bridge); returns null on the invalid
-  weapons/armament pairing, in which case the row contributes
-  zero.
+  armament })`; returns null on the invalid weapons/armament
+  pairing, in which case the row contributes zero.
 
 For `tech === "ALL"` every block whose mass is non-zero
 contributes against the player's race tech as the target. For
@@ -182,21 +181,18 @@ Per-action additional fields are documented on the
 `ui/frontend/src/sync/order-types.ts` next to the JSDoc for each
 variant.
 
-## Decisions baked into Phase 20
+## Design notes
 
-- **`BlockUpgradeCost` migrated to `pkg/calc`**. The cost
-  formula previously lived in
-  `game/internal/controller/ship_group_upgrade.go`. To keep the
-  `ui/core/calc` bridge a wrapper around pure `pkg/calc/`
-  formulas, the function moved to `pkg/calc/ship.go` and the
-  controller now imports it (`controller/ship_group_upgrade.go`).
+- **`BlockUpgradeCost` lives in `pkg/calc`**. The cost formula
+  lives in `pkg/calc/ship.go`; the `ui/core/calc` bridge wraps
+  pure `pkg/calc/` formulas, and the controller imports it
+  (`controller/ship_group_upgrade.go`).
 - **`GameReport.otherRaces`**. The transfer-to-race picker reads
-  from a new `GameReport.otherRaces: string[]` field, populated
-  by walking `report.player[]` and excluding the local race plus
-  every `extinct` entry. Phase 22 (Races View) reuses the same
-  field.
+  from `GameReport.otherRaces: string[]`, populated by walking
+  `report.player[]` and excluding the local race plus every
+  `extinct` entry. The Races View reuses the same field.
 - **Stationed-ship rows are clickable**. The map deliberately
   hides on-planet groups; the planet inspector's stationed-ship
-  rows now pivot the selection to the corresponding ship-group
+  rows pivot the selection to the corresponding ship-group
   variant so the actions panel is reachable from the standard
   click flow.