feat(ui): snow winter scene, rain panel size, and snow fixes

README.md

@@ -357,6 +357,24 @@ rain_animation_mode = "garden"
 halve growth speed, or `0.5` to roughly double it. The other knobs trade
 visual density (more or fewer seeds, longer or shorter blooms) for clarity.
 
+### Snow mode and rain panel size
+
+`rain_animation_mode = "snow"` uses the same animation strip for a winter scene:
+falling snowflakes, snow that keeps piling on the ground, a small log cabin
+with chimney smoke and lit windows, occasional evergreen trees that pick up
+frost, and a snowman that grows in stages (two spheres, then face, pipe, and
+top hat).
+
+`rain_panel_size` controls how many terminal rows the animation canvas uses:
+`compact` (5), `comfortable` (8, default), or `tall` (11). The TUI clamps the
+height automatically so the bordered panel still fits short terminals.
+
+```toml
+[ui]
+rain_animation_mode = "snow"
+rain_panel_size = "comfortable"
+```
+
 ### Config file, locks, and crashes
 
 **Registry (`repos.toml`)** — Writes use a cross-process lock file (`repos.toml.lock`), atomic replace, and stale-lock detection (owner PID). If a process dies mid-run you may still see a leftover lock: the CLI prompts to remove it when safe, or you can use **`--force-unlock-registry`** in scripts. This is the same class of “stale lock / don’t corrupt the database” problem as other multi-repo tools; treat lock removal like any other forced unlock — only when you are sure no other `git-rain` is running.

internal/config/config_test.go

@@ -9,9 +9,39 @@ import (
 	"github.com/git-rain/git-rain/internal/config"
 )
 
+func TestRainPanelRowsPresets(t *testing.T) {
+	tests := []struct {
+		in   string
+		want int
+	}{
+		{config.UIRainPanelCompact, 5},
+		{config.UIRainPanelComfortable, 8},
+		{config.UIRainPanelTall, 11},
+		{"", 8},
+		{"unknown-preset", 8},
+	}
+	for _, tc := range tests {
+		if got := config.RainPanelRows(tc.in); got != tc.want {
+			t.Errorf("RainPanelRows(%q) = %d, want %d", tc.in, got, tc.want)
+		}
+	}
+}
+
+func TestNormalizeRainPanelSize(t *testing.T) {
+	if got := config.NormalizeRainPanelSize(" TALL "); got != config.UIRainPanelTall {
+		t.Errorf("NormalizeRainPanelSize = %q, want %q", got, config.UIRainPanelTall)
+	}
+	if got := config.NormalizeRainPanelSize("compact"); got != config.UIRainPanelCompact {
+		t.Errorf("got %q", got)
+	}
+}
+
 func TestDefaultConfig_Values(t *testing.T) {
 	cfg := config.DefaultConfig()
 
+	if cfg.UI.RainPanelSize != config.UIRainPanelComfortable {
+		t.Errorf("default RainPanelSize = %q, want %q", cfg.UI.RainPanelSize, config.UIRainPanelComfortable)
+	}
 	if cfg.Global.BranchMode != "mainline" {
 		t.Errorf("default BranchMode = %q, want %q", cfg.Global.BranchMode, "mainline")
 	}

internal/config/defaults.go

@@ -37,11 +37,14 @@ func DefaultConfig() Config {
 		UI: UIConfig{
 			ShowRainAnimation:       true,
 			RainAnimationMode:       UIRainAnimationBasic,
+			RainPanelSize:           UIRainPanelComfortable,
 			ShowStartupQuote:        true,
 			StartupQuoteBehavior:    UIQuoteBehaviorRefresh,
 			StartupQuoteIntervalSec: DefaultUIStartupQuoteIntervalSec,
 			RainTickMS:              DefaultUIRainTickMS,
 			ColorProfile:            UIColorProfileStorm,
+			// SnowAccumulationRate 0 => runtime uses 1× (see SnowAccumPerLanding).
+			SnowAccumulationRate: 0,
 		},
 	}
 }
@@ -114,10 +117,14 @@ mainline_patterns = []
 show_rain_animation = true
 
 # Animation mode: "basic" (rain drops), "advanced" (clouds + rain + flowers),
-# "matrix" (falling code characters), or "garden" (seeds bloom into a meadow,
-# then the rain stops and the sun comes out)
+# "matrix" (falling code characters), "garden" (seeds bloom into a meadow,
+# then the rain stops and the sun comes out), or "snow" (winter scene)
 rain_animation_mode = "basic"
 
+# Animation canvas height: "compact" (5 rows), "comfortable" (8), or "tall" (11).
+# Clamped automatically if the terminal is short.
+rain_panel_size = "comfortable"
+
 # Show flavor quotes in the TUI banner
 show_startup_quote = true
 
@@ -133,6 +140,10 @@ rain_tick_ms = 150
 # Color profile: "storm", "drizzle", "monsoon", "rainbow", "synthwave"
 color_profile = "storm"
 
+# --- Snow mode (rain_animation_mode = "snow") -------------------------------
+# Ground depth added per landed flake (1–8). 1 = default; 3 ≈ three times faster piling.
+# snow_accumulation_rate = 1
+
 # --- Garden mode tuning (advanced) -----------------------------------------
 # These keys only affect rain_animation_mode = "garden". Leave them unset
 # (or at 0) to use the built-in defaults; tweak to make growth slower or

internal/config/loader.go

@@ -69,6 +69,8 @@ func LoadWithOptions(opts LoadOptions) (*Config, error) {
 		return nil, fmt.Errorf("invalid config: %w", err)
 	}
 
+	cfg.UI.RainPanelSize = NormalizeRainPanelSize(cfg.UI.RainPanelSize)
+
 	return &cfg, nil
 }
 
@@ -92,6 +94,7 @@ func setDefaults(v *viper.Viper) {
 
 	v.SetDefault("ui.show_rain_animation", defaults.UI.ShowRainAnimation)
 	v.SetDefault("ui.rain_animation_mode", defaults.UI.RainAnimationMode)
+	v.SetDefault("ui.rain_panel_size", defaults.UI.RainPanelSize)
 	v.SetDefault("ui.show_startup_quote", defaults.UI.ShowStartupQuote)
 	v.SetDefault("ui.startup_quote_behavior", defaults.UI.StartupQuoteBehavior)
 	v.SetDefault("ui.startup_quote_interval_sec", defaults.UI.StartupQuoteIntervalSec)
@@ -108,6 +111,7 @@ func setDefaults(v *viper.Viper) {
 	v.SetDefault("ui.garden_offspring_min", defaults.UI.GardenOffspringMin)
 	v.SetDefault("ui.garden_offspring_max", defaults.UI.GardenOffspringMax)
 	v.SetDefault("ui.garden_offspring_spread", defaults.UI.GardenOffspringSpread)
+	v.SetDefault("ui.snow_accumulation_rate", defaults.UI.SnowAccumulationRate)
 }
 
 // Bounded lock acquisition for config.toml: SaveConfig runs from the TUI on

internal/config/snow_accum_test.go

@@ -0,0 +1,25 @@
+package config
+
+import "testing"
+
+func TestSnowAccumPerLanding(t *testing.T) {
+	tests := []struct {
+		rate float64
+		want int
+	}{
+		{0, 1},
+		{-1, 1},
+		{1, 1},
+		{1.4, 1},
+		{1.5, 2},
+		{3, 3},
+		{8, 8},
+		{8.4, 8},
+		{99, 8},
+	}
+	for _, tt := range tests {
+		if got := SnowAccumPerLanding(tt.rate); got != tt.want {
+			t.Errorf("SnowAccumPerLanding(%v) = %d, want %d", tt.rate, got, tt.want)
+		}
+	}
+}

internal/config/types.go

@@ -1,6 +1,11 @@
 // Package config defines the git-rain configuration schema and related constants.
 package config
 
+import (
+	"math"
+	"strings"
+)
+
 // Config represents the complete git-rain configuration
 type Config struct {
 	Global GlobalConfig `mapstructure:"global" toml:"global"`
@@ -57,10 +62,15 @@ type UIConfig struct {
 	ShowRainAnimation bool `mapstructure:"show_rain_animation" toml:"show_rain_animation"`
 
 	// Animation mode: "basic" (rain drops), "advanced" (clouds + rain + flowers),
-	// "matrix" (falling code glyphs in the same column pattern), or "garden"
-	// (seeds, rain, growth, then sun).
+	// "matrix" (falling code glyphs in the same column pattern), "garden"
+	// (seeds, rain, growth, then sun), or "snow" (winter scene).
 	RainAnimationMode string `mapstructure:"rain_animation_mode" toml:"rain_animation_mode"`
 
+	// RainPanelSize is how tall the animation canvas is in the TUI: "compact",
+	// "comfortable", or "tall". The runtime clamps to the terminal so the panel
+	// still fits (see RainPanelRows).
+	RainPanelSize string `mapstructure:"rain_panel_size" toml:"rain_panel_size"`
+
 	// Show flavor quotes: TUI banner plus CLI motivation lines.
 	ShowStartupQuote bool `mapstructure:"show_startup_quote" toml:"show_startup_quote"`
 
@@ -111,6 +121,11 @@ type UIConfig struct {
 	// GardenOffspringSpread is the half-width X jitter applied around the
 	// parent column when scattering offspring seeds. 0 = default.
 	GardenOffspringSpread int `mapstructure:"garden_offspring_spread" toml:"garden_offspring_spread,omitempty"`
+
+	// SnowAccumulationRate scales how much ground snow depth each landed flake
+	// adds when rain_animation_mode = "snow". 1 = default; 2 ≈ twice as fast.
+	// Values are rounded to a whole number of depth units per landing (1..8).
+	SnowAccumulationRate float64 `mapstructure:"snow_accumulation_rate" toml:"snow_accumulation_rate,omitempty"`
 }
 
 const (
@@ -127,8 +142,38 @@ const (
 	UIRainAnimationAdvanced = "advanced"
 	UIRainAnimationMatrix   = "matrix"
 	UIRainAnimationGarden   = "garden"
+	UIRainAnimationSnow     = "snow"
+
+	UIRainPanelCompact     = "compact"
+	UIRainPanelComfortable = "comfortable"
+	UIRainPanelTall        = "tall"
 )
 
+// RainPanelRows returns the target animation height in terminal rows for a
+// panel size preset. Unknown or empty values use comfortable.
+func RainPanelRows(preset string) int {
+	switch strings.ToLower(strings.TrimSpace(preset)) {
+	case UIRainPanelCompact:
+		return 5
+	case UIRainPanelTall:
+		return 11
+	default:
+		return 8
+	}
+}
+
+// NormalizeRainPanelSize returns a canonical preset name.
+func NormalizeRainPanelSize(preset string) string {
+	switch strings.ToLower(strings.TrimSpace(preset)) {
+	case UIRainPanelCompact:
+		return UIRainPanelCompact
+	case UIRainPanelTall:
+		return UIRainPanelTall
+	default:
+		return UIRainPanelComfortable
+	}
+}
+
 // UIColorProfiles returns valid built-in UI color profile names.
 func UIColorProfiles() []string {
 	return []string{
@@ -139,3 +184,19 @@ func UIColorProfiles() []string {
 		UIColorProfileSynthwave,
 	}
 }
+
+// SnowAccumPerLanding returns ground depth units added per landed snowflake.
+// rate is cfg.UI.SnowAccumulationRate; 0 or negative means 1. Result is in [1, 8].
+func SnowAccumPerLanding(rate float64) int {
+	if rate <= 0 {
+		return 1
+	}
+	n := int(math.Round(rate))
+	if n < 1 {
+		return 1
+	}
+	if n > 8 {
+		return 8
+	}
+	return n
+}