Move LogDensityProblems + Markdown from weakdeps to direct deps

Fixes precompilation cycle: StanLogDensityProblems (direct dep) pulls in
LogDensityProblems, which triggered the LogDensityProblemsExt extension,
creating a circular dependency. Same issue with Markdown.

Fold both extensions into the main package and remove ext/ files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: nsiccha

Project.toml

@@ -7,23 +7,21 @@ version = "0.1.5"
 Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+LogDensityProblems = "6fdf6af0-433a-55f7-b3ed-c6c6e0b8df7c"
 LogExpFunctions = "2ab3a3ac-af41-5b50-aa03-7779005ae688"
+Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 OrderedCollections = "bac558e1-5e72-5ebc-8fee-abe8a469f55d"
 StanLogDensityProblems = "a545de4d-8dba-46db-9d34-4e41d3f07807"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [weakdeps]
 DifferentiationInterface = "a0c0ee7d-e4b9-4e03-894e-1c5f64a51d63"
-LogDensityProblems = "6fdf6af0-433a-55f7-b3ed-c6c6e0b8df7c"
-Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
 PosteriorDB = "1c4bc282-d2f5-44f9-b6d1-8c4424a23ad4"
 
 [extensions]
 DifferentiationInterfaceExt = "DifferentiationInterface"
-LogDensityProblemsExt = "LogDensityProblems"
-MarkdownExt = "Markdown"
 MooncakeExt = "Mooncake"
 OrdinaryDiffEqExt = "OrdinaryDiffEq"
 PosteriorDBExt = "PosteriorDB"

ext/LogDensityProblemsExt.jl

@@ -5,7 +5,7 @@ export @slic, @defsig, @deffun
 export stan_code, stan_model, stan_instantiate
 export StanBlocksError
 
-using LinearAlgebra, Statistics, Distributions, LogExpFunctions, JSON, StanLogDensityProblems
+using LinearAlgebra, Statistics, Distributions, LogExpFunctions, JSON, StanLogDensityProblems, LogDensityProblems, Markdown
 
 # --- Error type for StanBlocks computations (defined early so submodules can use it) ---
 
@@ -35,6 +35,19 @@ slic_implementation(key; kwargs...) = nothing
 stan_implementation(key; kwargs...) = missing
 include("check.jl")
 
+# --- LogDensityProblems interface ---
+LogDensityProblems.capabilities(::Type{VectorPosterior{F,G,GQ,N}}) where{F,G,GQ,N} = if G == Missing
+    LogDensityProblems.LogDensityOrder{0}()
+else
+    LogDensityProblems.LogDensityOrder{1}()
+end
+LogDensityProblems.dimension(p::VectorPosterior) = dimension(p)
+LogDensityProblems.logdensity(p::VectorPosterior, x) = p(x)
+LogDensityProblems.logdensity_and_gradient(p::VectorPosterior, x) = p.g(x)
+
+# --- Markdown/Quarto display ---
+include("quarto.jl")
+
 # --- Error display for StanBlocks computations ---
 
 _cause_error(e::StanBlocksError) = e.cause isa Tuple ? e.cause[1] : e.cause

src/StanBlocks.jl

@@ -1,22 +1,18 @@
-module MarkdownExt
-import Markdown, StanBlocks
-import StanBlocks: quarto
-
-module Quarto 
+module Quarto
     using Markdown
     abstract type Object end
     struct Container <: Object
         children
     end
-    struct Heading <: Object 
+    struct Heading <: Object
         level
         obj
     end
     struct Div <: Object
         header
         content
     end
-    struct Code <: Object 
+    struct Code <: Object
         header
         content
     end
@@ -44,7 +40,7 @@ module Quarto
         print(io, child, "\n")
     end
     Base.show(io::IO, x::Heading) = print(io, repeat("#", x.level), " ", x.obj, "\n")
-    Base.show(io::IO, x::Div) = begin 
+    Base.show(io::IO, x::Div) = begin
         print(io, "\n::: ", x.header, "\n\n")
         print(io, x.content)
         print(io, "\n:::\n")
@@ -61,20 +57,9 @@ module Quarto
     end
 end
 
-mapkv(f, x) = map(f, keys(x), values(x))
-msg(e) = try 
-    string(e)
-catch
-    "Something went wrong!"
-end
-msg(e::ErrorException) = msg(e.msg)
-
-Base.show(io::IO, m::MIME"text/markdown", x::StanBlocks.stan.SlicModel) = show(io, m, quarto(x))
+Base.show(io::IO, m::MIME"text/markdown", x::stan.SlicModel) = show(io, m, quarto(x))
 
-quarto(x::StanBlocks.stan.SlicModel) = Quarto.Container([
+quarto(x::stan.SlicModel) = Quarto.Container([
     Quarto.Heading(5, "SlicModel"),
-    Quarto.Tabset((;stan=Quarto.Code("stan", StanBlocks.stan_code(x)), julia=Quarto.Code("julia", x.model)))
+    Quarto.Tabset((;stan=Quarto.Code("stan", stan_code(x)), julia=Quarto.Code("julia", x.model)))
 ])
-
-
-end