Apply authored Age environment symbols (#34)

docs/AGE_PROFILES.md

@@ -47,9 +47,11 @@ in the Binder. Bundled controls are Native, Single, Tiled, Grid, and Tiny throug
 Huge regions. Single needs one distinct biome; Tiled/Grid and Tiny–Huge need
 two. An authored book receives seeded filler only when it falls below that
 minimum, while extra authored pages are retained as weighted entries. A book
-with no biome pages selects a seeded count from 2–4 for Tiled/Grid or 2–6 for
-Tiny–Huge, capped by the number of eligible terrain biomes. Single uses one;
-Native uses its preset biome pool. These random-age maximums do not truncate
+with no biome pages selects a seeded count from two up to the number of
+eligible biomes for Tiled/Grid and Tiny–Huge. The eligible pool comes from the
+terrain's biome preset, or `#rivencraft:cave_biomes` for Cave terrain, so future
+biome integrations can expand it without changing the count rule. Single uses
+one; Native uses its preset biome pool. This random-age maximum does not truncate
 authored pages: the Binder's 27 symbol-page positions bound an authored book.
 Native cannot be paired with explicit biome pages. Legacy filled Tiny–Huge to
 three; Rivencraft deliberately uses two so a pair of written biome pages stays
@@ -79,6 +81,28 @@ eligible fallback for that load; restoring the biome recovers the original
 selection. Generation-version-15 Ages keep their prior registry-wide biome
 selection algorithm instead of being silently regenerated.
 
+## Written environment
+
+Lighting pages select Normal, Dark, or Bright lighting for the new Age. A Sky
+page selects Minecraft's Overworld, Nether, or End sky effects; the chosen
+effects also determine the destination preview backdrop. Overworld sky tint
+continues to come from the destination biome. A written sky changes only that
+Age's dimension type, not the source world or other Ages.
+
+Normal, Fast, Slow, Off, Always, and Storm weather pages use the existing Age
+weather controller. Zero, Half, Full, and Double Length pages set the day-cycle
+period, and Nadir, Rising, Zenith, and Setting pages set its initial phase.
+Repeated numeric modifiers combine in written order. A Zero Length Age keeps
+the nonzero minimum clock rate that avoids client skybox bounce. Pages for
+Cloudy, forced Rain, and Snow are not offered: vanilla precipitation rendering
+cannot reproduce those Legacy distinctions yet, and Snow remains planned for
+the optional season integrations. A data pack that supplies these unsupported
+weather choices receives a binding error rather than a false success.
+
+The Pages creative tab and optional JEI page ingredients use the same generated
+index of bundled environment symbols. Existing Age definitions and page-free
+random Ages retain their saved or seeded environment unchanged.
+
 ## Persistence and reload behavior
 
 An Age permanently stores its selected profile ID, generation version, seed,

docs/GAMETESTS.md

@@ -8,7 +8,7 @@ data migration, workstation transactions, and forged/replayed menu actions.
 ./gradlew runGameTestServer
 ```
 
-The remaining 56 Rivencraft tests are archived, not deleted. They cover
+The remaining 58 Rivencraft tests are archived, not deleted. They cover
 completed milestone details such as every Age terrain profile, Notebook and
 Desk surface interactions, refill edge cases, book assembly controls, and
 workstation break/drop behavior. Run only the relevant archive alongside the
@@ -19,8 +19,8 @@ core tests when investigating an issue:
 ./gradlew runGameTestServer -ParchivedGameTestSuites=grammar,binder
 ```
 
-Available suite names are `linking`, `writing`, `grammar`, `desk`, `binder`, `mixer`, and
-`recipe`. Run all 79 Rivencraft tests before a
+Available suite names are `linking`, `environment`, `writing`, `grammar`, `desk`,
+`binder`, `mixer`, and `recipe`. Run all 81 Rivencraft tests before a
 release or after broad cross-system changes:
 
 ```shell

docs/WRITING_DATA.md

@@ -34,10 +34,9 @@ Invalid definitions are logged and excluded by the server. Menus and future
 page synchronization must obtain resolved display metadata from the server;
 clients never make a symbol valid by naming it.
 
-Rivencraft ships a small catalog covering terrain, biomes, lighting, weather,
-celestial behavior, and features. Its v2 semantics prepare for the full
-Legacy-inspired grammar; writing still uses random Age fallback until the
-parser and compiler are implemented.
+Rivencraft ships a catalog covering terrain, biomes, lighting, weather,
+sky, celestial behavior, and features. The parser and compiler apply supported
+schema-v2 pages to newly created Ages; omitted branches retain seeded defaults.
 
 ## Persistent writing
 
@@ -54,9 +53,7 @@ book copies its writing and Age reference; merely copying it never creates a
 new Age. The Book Binder creates the Age when its finished output is taken.
 The Descriptive Book screen can inspect the ordered pages by turning them from
 the bottom corners and identifies unresolved IDs using server-provided symbol
-metadata. Until Milestone 5, the
-saved symbols are informational only: Age creation uses the existing random
-fallback and does not apply them to generation.
+metadata. Page-free books continue to use random Age generation.
 
 Removing a data pack never removes its IDs from saved writing. A missing ID is
 resolved as client-safe **Unresolved Symbol** display metadata while retaining
@@ -108,7 +105,8 @@ imported at a chosen strip position; the empty Notebook remains recoverable.
 The preview result is virtual. Taking the completed Descriptive Book commits the
 inputs once, creates its Age identity, and saves schema-versioned
 `OrderedWriting` plus the Age reference on the book. Link-Panel-only books
-create random Ages. A written symbol does **not** yet change that generation.
+create random Ages. Supported written pages change the corresponding Age
+generation branch; missing branches use seeded defaults.
 Inputs, title, and pending Age identity survive Binder save/load; breaking the
 Binder returns stored inputs. The completed book retains both its writing and
 Age identity through item save/load and copying.

docs/WRITING_GRAMMAR.md

@@ -4,10 +4,10 @@
 
 New Binder writing has at most one Link Panel plus 27 symbol pages. The Link Panel must be first. A Link-Panel-only book, or an older book with no writing component, keeps the existing random Age path. Any authored supported symbol makes the book a partial or complete grammar. From 0.4.3.0, the server compiles it into a persistent Age plan before consuming Binder inputs or generating chunks.
 
-The supported order follows the representable subset of the [Legacy grammar audit](LEGACY_AGE_GRAMMAR_AUDIT.md): terrain; zero or more biome pages; biome controller; weather; lighting; zero or more period, angle, or phase modifiers; one celestial page; then zero or more distinct features. Biome pages precede the controller that consumes them, and celestial modifiers precede the celestial page. Terrain, controller, weather, lighting, and celestial are single-choice categories; identical repeats are duplicates and differing values conflict. Repeated modifiers are intentional. Biome pages may repeat, preserving author order and any future weighting; feature IDs may not repeat.
+The supported order follows the representable subset of the [Legacy grammar audit](LEGACY_AGE_GRAMMAR_AUDIT.md): terrain; zero or more biome pages; biome controller; weather; lighting; sky effects; zero or more period or phase modifiers; one celestial page; then zero or more distinct features. Biome pages precede the controller that consumes them, and celestial modifiers precede the celestial page. Terrain, controller, weather, lighting, sky, and celestial are single-choice categories; identical repeats are duplicates and differing values conflict. Repeated modifiers are intentional. Biome pages may repeat, preserving author order and any future weighting; feature IDs may not repeat. Angle modifiers remain recognized in the schema but are rejected at binding until a sky renderer can apply sun tilt.
 
 Missing terrain, controller, weather, lighting, celestial, or the controller's minimum biome count is an **incomplete** warning, not an error: the compiler retains the seed-selected profile and traits for missing branches. The minimum is zero for Native, one for Single, and two for Tiled/Grid and Tiny–Huge. Native cannot consume authored biome pages; Single accepts only one. Unknown IDs, schema-v1 display-only symbols, wrong ordering, misplaced modifiers, duplicates, conflicts, missing/extra Link Panels, and oversized writing are errors. The Binder disables output and exposes the first error on the result-slot tooltip. When that error belongs to a page, its thumbnail is tinted and outlined red, the strip scrolls to it, and hovering it shows the diagnostic. This maps the parser's compact entry position back through any empty page positions. Rejected inputs remain removable. Binding an unwritten Descriptive Book rechecks its server-owned writing and reports the first error without creating an Age. A terrain symbol whose profile is unavailable is also rejected before Binder inputs are consumed.
 
-The plan stores the original writing order, the authoritative semantic value of each resolved symbol, the Age seed, and a copy of the selected runtime profile. An explicit terrain page replaces the random terrain selection; an omitted terrain uses the seed-selected profile. The built-in Standard, Amplified, Cave, Island, Flat, and Void terrain pages now select their matching generation resources. Age loading uses the frozen runtime profile and does not need the original symbol definition or runtime-profile JSON, though its referenced noise, biome-preset, and dimension-type registry entries must remain available. Existing bound books without plans are not reinterpreted. Page-free and Link-Panel-only books keep the pre-existing random path. Biome, lighting, weather, celestial, and feature effects are retained in the plan but will be applied in issues #33–#35; instability remains Milestone 6 work.
+The plan stores the original writing order, the authoritative semantic value of each resolved symbol, the Age seed, and a copy of the selected runtime profile. An explicit terrain page replaces the random terrain selection; an omitted terrain uses the seed-selected profile. The built-in Standard, Amplified, Cave, Island, Flat, and Void terrain pages select their matching generation resources. Age loading uses the frozen runtime profile and does not need the original symbol definition or runtime-profile JSON, though its referenced noise, biome-preset, and dimension-type registry entries must remain available. Existing bound books without plans are not reinterpreted. Page-free and Link-Panel-only books keep the pre-existing random path. Biome and environment pages now affect new Ages; feature effects remain issue #35 work, and instability remains Milestone 6 work.
 
 The Rivencraft Pages creative tab reads a generated index of bundled symbol definitions. Adding another valid JSON symbol under `src/main/resources/data/rivencraft/rivencraft/symbols/` includes its page automatically in the next build; no Java starter-page list needs updating. The server catalog still decides whether that page is valid for writing. External server data-pack symbols are not included in this bundled index.