chore: move executable code to src/

src/ now contains all source code - in subdirectories, according to the
.cabal component they belong to. This will allow us to put vendored
libraries in the same place - and later split our own code into multiple
components/libraries as well.

nix/hsie/README.md

@@ -5,10 +5,10 @@ project. It's available in PostgREST's `nix-shell` by default.
 
 ## Dumping imports
 
-Given source code in the directories `src` and `main`, for example, you can run:
+Given source code in the directories `src/library` and `src/executable`, for example, you can run:
 
 ```
-hsie dump-imports src main
+hsie dump-imports src/library src/executable
 ```
 
 This dumps all imports of the modules in the given directory to a CSV file,
@@ -18,7 +18,7 @@ To dump to a JSON file (e.g., to further process with `jq`), add the `--json`
 flag:
 
 ```
-hsie dump-imports --json src main
+hsie dump-imports --json src/library src/executable
 ```
 
 ## Graphing imports
@@ -27,7 +27,7 @@ The tool can generate `graphviz` graphs of module and symbol imports by printing
 a file to `stdout` that can directly be rendered with `dot`:
 
 ```
-hsie graph-modules src main | dot -Tpng -o modules.png
+hsie graph-modules src/library src/executable | dot -Tpng -o modules.png
 ```
 
 The command `graph-modules` prints a graph of which modules insert which other
@@ -39,7 +39,7 @@ To check whether modules are imported under consistent aliases in your project,
 run:
 
 ```
-hsie check-aliases main src
+hsie check-aliases src/library src/executable
 ```
 
 This will exit with a non-zero exit code if any inconsistent aliases are found.
@@ -48,13 +48,13 @@ The following command checks whether any modules are imported as wildcards, i.e.
 not qualified and without specifying symbols.
 
 ```
-hsie check-wildcards main src
+hsie check-wildcards src/library src/executable
 ```
 
 To whitelist certain modules to be imported as wildcards, use `--ok`:
 
 ```
-hsie check-wildcards main src --ok Protolude --ok Test.Module
+hsie check-wildcards src/library src/executable --ok Protolude --ok Test.Module
 ```
 
 ## Current limitations

nix/tools/devTools.nix

@@ -132,7 +132,7 @@ let
         args = [ "ARG_OPTIONAL_SINGLE([outfile], [o], [Output filename], [postgrest-module-graph.png])" ];
       }
       ''
-        ${hsie} graph-modules main src | ${graphviz}/bin/dot -Tpng -o "$_arg_outfile"
+        ${hsie} graph-modules src/library src/executable | ${graphviz}/bin/dot -Tpng -o "$_arg_outfile"
       '';
 
   hsieGraphSymbols =

nix/tools/style.nix

@@ -88,7 +88,7 @@ let
         ${ruff}/bin/ruff check .
 
         echo "Checking consistency of import aliases in Haskell code..."
-        ${hsie} check-aliases main src
+        ${hsie} check-aliases src/library src/executable
 
         echo "Linting Haskell files..."
         ${fd}/bin/fd '\.l?hs$' \