Updates documentation.

docs/modernization-plan.md

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+# Metropolis Modernization Plan
+
+This is the maintained status and follow-up plan. Implemented behavior is
+described in [README.md](../README.md); automated and manual coverage are
+separated in [human-tests.md](human-tests.md). A feature is not considered
+runtime-verified merely because its code or an isolated unit test exists.
+
+## Completed
+
+- **Build and CI modernization.** Gradle 9.8 builds the Java 25 plugin and
+  expands the version into `plugin.yml`. CI runs `test` and the plugin build
+  for pushes and pull requests to `develop`. Completion check: running
+  `./gradlew test build` succeeds; CI provides the corresponding hosted check.
+- **Paper/WorldGuard/WorldEdit integration.** The plugin declares Paper API
+  26.2, WorldGuard 7.0.19, and WorldEdit 7.4.5, and uses WorldGuard regions
+  for city, home, and reservation geometry. Paper 26.2/26.3 are project
+  targets; the current build and CI do not perform live server compatibility
+  checks. Completion check for runtime claims: run the applicable manual
+  scenarios in `human-tests.md` on a disposable server.
+- **Plot, home, and command features.** The implementation includes join-time
+  initial home allocation, explicit additional-home acquisition, UUID-based
+  active-home persistence with legacy name-key loading, user/permission plot
+  overrides, reservations, multi-level support checks, and configured
+  road/stair generation. Isolated tests cover parts of these rules; see
+  `src/test/` and `human-tests.md` for their boundaries.
+
+## Pending
+
+- **Expand live-server integration coverage.** The current `integrationTest`
+  suite only checks plugin visibility and persistence of one coordinate-based
+  WorldGuard reservation. Add focused disposable-server checks for join-time
+  home allocation/ownership and selected-home restart persistence. Completion
+  criteria: tests assert the expected region/UUID state before and after a
+  restart, clean up their own test regions, and remain excluded from `build`.
+- **Choose optional login allocation policies (MET-023/MET-024).** Current
+  behavior allocates the configured initial home count (default one) when a
+  player has no home; later homes require `/metropolis-home-acquire`. Decide
+  whether to offer grant-all-to-limit or one-more-per-login policies before
+  implementing them. Completion criteria: documented config semantics,
+  compatibility defaults, and unit tests for limits, reconnects, and existing
+  home selections.
+- **Choose an allocation traversal option (MET-025).** The proposal to select
+  a rectangle/cuboid or ring-based traversal remains unimplemented. First
+  document deterministic ordering and how each policy treats occupied regions,
+  levels, and WorldBorder bounds. Completion criteria: configuration and
+  focused allocation tests establish repeatable ordering without overlaps.
+- **Research conversion of existing worlds (MET-026).** There is no automatic
+  world/config conversion workflow. Document the legacy data/config formats,
+  backups and rollback requirements, and a safe migration strategy before
+  proposing implementation. Completion criteria: a reviewed conversion
+  specification plus disposable-world validation; do not claim migration
+  support before that work is complete.
+
+## Deferred Ideas
+
+Economy-based home sales, arbitrary connected plot shapes, and alternate
+multi-plot footprints remain product ideas, not committed work. Reconsider them
+only after requirements, compatibility constraints, and acceptance criteria
+are defined.