feat: project build system with lib/bin separation

- Add src/project.nim: parse bara.edn manifest (name, version, lib, bins)
- Add cljnim build / cljnim build --mono commands
- Compile lib modules once to target/nim/lib_*.nim with exported defs
- Cross-module symbol resolution via from/import nil + fully qualified names
- Emitter: lib mode with * export markers, variadic seq[CljVal] handling

src/emitter.nim

@@ -5,6 +5,7 @@ import macros
 
 var requiredImports* = initHashSet[string]()
 var emitLibMode* = false
+var emitEntryProcName* = ""
 var loopStack*: seq[seq[string]] = @[]
 var nsAliases*: seq[(string, string)] = @[]  # (alias, namespace)
 var scopeStack*: seq[HashSet[string]] = @[]
@@ -82,6 +83,21 @@ proc clearGlobals*() =
 proc setNsAliases*(aliases: seq[(string, string)]) =
   nsAliases = aliases
 
+var libNsPrefixes*: seq[string] = @[]
+
+proc setLibNsPrefixes*(prefixes: seq[string]) =
+  libNsPrefixes = prefixes
+
+proc sanitizeNimIdent*(name: string): string
+
+proc nsToNimModuleName(ns: string): string =
+  result = "lib_"
+  for c in ns:
+    case c
+    of '.', '-': result.add('_')
+    of 'a'..'z', 'A'..'Z', '0'..'9', '_': result.add(c)
+    else: result.add('_')
+
 proc resolveNsAlias*(name: string): string =
   # Resolve mu/square -> square (strip namespace prefix if alias exists)
   let slashIdx = name.find('/')
@@ -90,6 +106,9 @@ proc resolveNsAlias*(name: string): string =
   let suffix = name[slashIdx+1..^1]
   for (alias, ns) in nsAliases:
     if prefix == alias:
+      if prefix in libNsPrefixes:
+        # Return fully qualified name for lib module symbols
+        return nsToNimModuleName(ns) & ".clj_" & sanitizeNimIdent(suffix)
       return suffix
   return name
 
@@ -130,6 +149,10 @@ proc sanitizeNimIdent*(name: string): string =
     result = "x" & result
   if result.len == 0:
     result = "val"
+  # Avoid conflicts with runtime functions: all-uppercase short names (GET, POST, etc)
+  # get a suffix so they don't collide with cljGet, cljSet, etc.
+  if result.len > 0 and result.allCharsInSet({'A'..'Z', '_'}) and result.len <= 7:
+    result.add("X")
   # Nim keywords that would clash
   let nimKeywords = ["in", "out", "var", "let", "proc", "func", "type", "ref", "ptr",
                      "object", "method", "template", "macro", "iterator", "converter",
@@ -732,7 +755,8 @@ proc emitSpecialForm(items: seq[CljVal], indent: int, needsValue: bool = false):
         let mangled = mangleName(nameItem.symName)
         registerGlobal(nameItem.symName)
         let valCode = emitExpr(valItem, 0, needsValue = true)
-        return sp & "let " & mangled & " = " & valCode
+        let exportMarker = if emitLibMode: "*" else: ""
+        return sp & "let " & mangled & exportMarker & " = " & valCode
       return sp & "cljNil()"
     var name = items[1]
     # Strip metadata: (with-meta sym meta) -> sym
@@ -748,6 +772,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int, needsValue: bool = false):
     # Special handling: (def name (fn ...)) should emit raw proc, not cljFn wrapper
     let isFnDef = valForm.kind == ckList and valForm.items.len > 0 and
                   valForm.items[0].kind == ckSymbol and valForm.items[0].symName == "fn"
+    let exportMarker = if emitLibMode: "*" else: ""
     if indent == 0:
       if isFnDef:
         # Emit fn as raw proc for def context
@@ -755,9 +780,9 @@ proc emitSpecialForm(items: seq[CljVal], indent: int, needsValue: bool = false):
         emitLibMode = false
         let valCode = emitFnAsProc(valForm.items, 0)
         emitLibMode = oldEmitLibMode
-        return sp & "let " & mangled & " = " & valCode
+        return sp & "let " & mangled & exportMarker & " = " & valCode
       let valCode = emitExpr(items[2], 0, needsValue = true)
-      return sp & "let " & mangled & " = " & valCode
+      return sp & "let " & mangled & exportMarker & " = " & valCode
     else:
       # For nested def: use global var so it's accessible from closures
       if isFnDef:
@@ -765,9 +790,9 @@ proc emitSpecialForm(items: seq[CljVal], indent: int, needsValue: bool = false):
         emitLibMode = false
         let valCode = emitFnAsProc(valForm.items, indent)
         emitLibMode = oldEmitLibMode
-        return sp & "var " & mangled & " = " & valCode.strip() & "\n" & sp & mangled
+        return sp & "var " & mangled & exportMarker & " = " & valCode.strip() & "\n" & sp & mangled
       let valCode = emitExpr(items[2], indent, needsValue = true)
-      return sp & "var " & mangled & " = " & valCode.strip() & "\n" & sp & mangled
+      return sp & "var " & mangled & exportMarker & " = " & valCode.strip() & "\n" & sp & mangled
 
   of "defn":
     if items.len < 3:
@@ -896,7 +921,14 @@ proc emitSpecialForm(items: seq[CljVal], indent: int, needsValue: bool = false):
       else:
         bodyCode = emitBlock(body, indent + 1)
       popScope()
-      return sp & "proc " & procName & exportMarker & "(" & paramNames.join(", ") & "): CljVal =\n" & bodyCode
+      var result = sp & "proc " & procName & exportMarker & "(" & paramNames.join(", ") & "): CljVal =\n" & bodyCode
+      if emitLibMode and paramNames.len > 0 and not (name.symName in multiArityFns):
+        var wrapperArgs: seq[string] = @[]
+        for i in 0..<paramNames.len:
+          wrapperArgs.add("args[" & $i & "]")
+        result.add("\n" & sp & "proc " & procName & exportMarker & "(args: seq[CljVal]): CljVal =\n")
+        result.add(indentStr(indent + 1) & procName & "(" & wrapperArgs.join(", ") & ")\n")
+      return result
     else:
       var bodyCode = ""
       if body.len == 1:
@@ -2181,6 +2213,10 @@ proc emitSpecialForm(items: seq[CljVal], indent: int, needsValue: bool = false):
     var callOp = op
     if callOp.endsWith("."):
       callOp = callOp[0..^2]
+    let baseOp = if callOp.contains("/"): callOp.split("/")[1] else: callOp
+    let resolvedOp = resolveNsAlias(callOp)
+    if resolvedOp.contains("."):
+      return sp & resolvedOp & "(@[" & args.join(", ") & "])"
     let mangled = mangleName(callOp)
     # Multi-arity function: wrap args in seq
     if callOp in multiArityFns:
@@ -2247,6 +2283,9 @@ proc emitExpr*(v: CljVal, indent: int = 0, needsValue: bool = false): string =
     return sp & "cljKeyword(\"" & v.kwName & "\")"
   of ckSymbol:
     let symName = resolveNsAlias(v.symName)
+    # If symName contains a dot, it's a fully qualified lib module reference
+    if symName.contains("."):
+      return sp & symName
     let rn = runtimeName(symName)
     if rn.len > 0 and not isLocalVar(symName):
       # Check if the runtime function is variadic (takes seq[CljVal])
@@ -2443,9 +2482,17 @@ proc emitProgramInternal(forms: seq[CljVal]): string =
       for form in mainForms:
         lines.add(form)
     else:
-      lines.add("when isMainModule:")
-      for form in mainForms:
-        lines.add(form)
+      if emitEntryProcName.len > 0:
+        lines.add("proc " & emitEntryProcName & "*(args: seq[CljVal] = @[]): CljVal =")
+        for form in mainForms:
+          lines.add(form)
+        lines.add("")
+        lines.add("when isMainModule:")
+        lines.add("  discard " & emitEntryProcName & "()")
+      else:
+        lines.add("when isMainModule:")
+        for form in mainForms:
+          lines.add(form)
 
   return lines.join("\n") & "\n"