feat(makie): implement hexbin-map-geographic (#7751)

## Implementation: `hexbin-map-geographic` - julia/makie

Implements the **julia/makie** version of `hexbin-map-geographic`.

**File:** `plots/hexbin-map-geographic/implementations/julia/makie.jl`

**Parent Issue:** #3767

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/26514203873)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Markus Neusinger <2921697+MarkusNeusinger@users.noreply.github.com>

Author: github-actions[bot]

plots/hexbin-map-geographic/implementations/julia/makie.jl

@@ -0,0 +1,152 @@
+# anyplot.ai
+# hexbin-map-geographic: Hexagonal Binning Map
+# Library: makie 0.22.10 | Julia 1.11.9
+# Quality: 85/100 | Created: 2026-05-27
+
+using CairoMakie
+using Colors
+using Random
+
+Random.seed!(42)
+
+# Theme tokens
+const THEME       = get(ENV, "ANYPLOT_THEME", "light")
+const PAGE_BG     = THEME == "light" ? colorant"#FAF8F1" : colorant"#1A1A17"
+const ELEVATED_BG = THEME == "light" ? colorant"#FFFDF6" : colorant"#242420"
+const INK         = THEME == "light" ? colorant"#1A1A17" : colorant"#F0EFE8"
+const INK_SOFT    = THEME == "light" ? colorant"#4A4A44" : colorant"#B8B7B0"
+const INK_MUTED   = THEME == "light" ? colorant"#6B6A63" : colorant"#A8A79F"
+const GRID_COLOR  = THEME == "light" ?
+    RGBAf(26/255f0, 26/255f0, 23/255f0, 0.12f0) :
+    RGBAf(240/255f0, 239/255f0, 232/255f0, 0.12f0)
+
+# Water fill and coastline colors for the geographic base map
+const WATER_FILL  = THEME == "light" ?
+    RGBAf(0.58f0, 0.75f0, 0.88f0, 0.32f0) :
+    RGBAf(0.18f0, 0.35f0, 0.56f0, 0.45f0)
+const COAST_LINE  = THEME == "light" ?
+    RGBAf(0.27f0, 0.46f0, 0.63f0, 0.65f0) :
+    RGBAf(0.42f0, 0.62f0, 0.80f0, 0.52f0)
+
+# Anyplot sequential colormap for density (single-polarity)
+const ANYPLOT_SEQ = cgrad([colorant"#009E73", colorant"#4467A3"])
+
+# Data: synthetic bike-share ride starts in San Francisco
+cluster_centers = [
+    (-122.4057, 37.7871),  # Union Square / Downtown
+    (-122.4194, 37.7599),  # Mission District
+    (-122.3971, 37.7749),  # SoMa
+    (-122.4352, 37.8012),  # Marina
+    (-122.4447, 37.7698),  # Haight-Ashbury
+]
+cluster_weights = [0.33, 0.22, 0.20, 0.13, 0.12]
+cluster_stds    = [0.013, 0.012, 0.011, 0.010, 0.013]
+
+n_total = 14000
+lons = Float64[]
+lats = Float64[]
+
+for ((cx, cy), w, σ) in zip(cluster_centers, cluster_weights, cluster_stds)
+    n_i = round(Int, n_total * w)
+    append!(lons, cx .+ σ .* randn(n_i))
+    append!(lats, cy .+ σ .* randn(n_i))
+end
+
+# Map extent — tightened from original to reduce empty ocean space upper-left
+lon_lo, lon_hi = -122.515, -122.360
+lat_lo, lat_hi =   37.700,   37.835
+
+# Clip to bounds
+mask = (lons .>= lon_lo) .& (lons .<= lon_hi) .& (lats .>= lat_lo) .& (lats .<= lat_hi)
+lons = lons[mask]
+lats = lats[mask]
+
+# --- Simplified geographic base map -----------------------------------------
+# Polygon vertices tracing simplified SF coastlines; Makie auto-closes last→first.
+
+# SF Bay water polygon: follows the eastern SF waterfront (south→north),
+# then closes via the box top-right corner and right edge.
+bay_pts = Point2f[
+    (-122.374, 37.700), (-122.376, 37.748), (-122.381, 37.762),
+    (-122.386, 37.776), (-122.393, 37.790), (-122.400, 37.800),
+    (-122.407, 37.805), (-122.414, 37.808), (-122.432, 37.804),
+    (-122.443, 37.803), (-122.455, 37.803), (-122.464, 37.804),
+    (-122.479, 37.808),                       # Golden Gate Bridge — SF side
+    (-122.479, 37.835), (-122.360, 37.835), (-122.360, 37.700),
+]
+
+# Pacific Ocean polygon: follows the western SF coast (north→south),
+# then closes via the box bottom-left and left edge back to the top.
+pac_pts = Point2f[
+    (-122.479, 37.808),                       # Golden Gate Bridge — SF side
+    (-122.484, 37.800), (-122.493, 37.798),
+    (-122.499, 37.794), (-122.505, 37.789),
+    (-122.509, 37.782), (-122.511, 37.770),
+    (-122.512, 37.748), (-122.511, 37.710),
+    (-122.515, 37.700), (-122.515, 37.835),
+    (-122.479, 37.835),
+]
+
+# --- Figure -----------------------------------------------------------------
+fig = Figure(
+    size            = (1600, 900),
+    fontsize        = 14,
+    backgroundcolor = PAGE_BG,
+)
+
+ax = Axis(
+    fig[1, 1];
+    title              = "SF Bike-Share · hexbin-map-geographic · julia · makie · anyplot.ai",
+    titlesize          = 20,
+    titlecolor         = INK,
+    xlabel             = "Longitude",
+    ylabel             = "Latitude",
+    xlabelsize         = 14,
+    ylabelsize         = 14,
+    xticklabelsize     = 12,
+    yticklabelsize     = 12,
+    xlabelcolor        = INK,
+    ylabelcolor        = INK,
+    xticklabelcolor    = INK_SOFT,
+    yticklabelcolor    = INK_SOFT,
+    xtickcolor         = INK_SOFT,
+    ytickcolor         = INK_SOFT,
+    backgroundcolor    = PAGE_BG,
+    topspinevisible    = false,
+    rightspinevisible  = false,
+    leftspinecolor     = INK_SOFT,
+    bottomspinecolor   = INK_SOFT,
+    xgridcolor         = GRID_COLOR,
+    ygridcolor         = GRID_COLOR,
+    xminorgridvisible  = false,
+    yminorgridvisible  = false,
+)
+
+# Base map: water bodies rendered before hexbins so land clusters stay visible
+poly!(ax, bay_pts; color = WATER_FILL, strokecolor = COAST_LINE, strokewidth = 1.2)
+poly!(ax, pac_pts; color = WATER_FILL, strokecolor = COAST_LINE, strokewidth = 1.2)
+
+# Hexagonal density map overlaid on base map
+hb = hexbin!(ax, lons, lats;
+    cellsize    = 0.009,
+    colormap    = ANYPLOT_SEQ,
+    threshold   = 1,
+    strokecolor = PAGE_BG,
+    strokewidth = 0.5,
+)
+
+# Colorbar
+Colorbar(fig[1, 2], hb;
+    label           = "Ride Count",
+    labelsize       = 13,
+    labelcolor      = INK,
+    ticklabelsize   = 11,
+    ticklabelcolor  = INK_SOFT,
+    tickcolor       = INK_SOFT,
+    width           = 18,
+)
+
+limits!(ax, lon_lo, lon_hi, lat_lo, lat_hi)
+colgap!(fig.layout, 12)
+
+save("plot-$(THEME).png", fig; px_per_unit = 2)