Phase 0: scaffold tree + manifest

- README, .gitignore, CLAUDE.md (project conventions)
- docs/PHASE0.md — full Phase 0 manifest (locked substrate)
- 10 root .lua modules + 4 ffi/ bindings, all stubs raising NotImplemented
  with module-scoped responsibilities matching the manifest
- config.lua wired to current dirac/hossenfelder endpoints (qwen-coder-7b
  snappy/32k + cloud via OpenRouter through hossenfelder)

File names match docs/PHASE0.md §4 exactly. Module bodies fill in across
later phases; the tree shape is locked.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

repl.lua

@@ -0,0 +1,25 @@
+-- repl.lua — readline loop, input dispatch, prompt rendering.
+-- See docs/PHASE0.md §5, §9.
+
+local M = {}
+
+-- Phase 0 stub.
+function M.run(config)
+    error("repl.run: not implemented (Phase 0 pending)")
+end
+
+-- Meta command table per PHASE0.md §5.2.
+M.meta_commands = {
+    quit    = function(ctx) os.exit(0) end,
+    q       = function(ctx) os.exit(0) end,
+    clear   = nil,    -- TODO Phase 0 impl
+    reset   = nil,
+    model   = nil,
+    models  = nil,
+    history = nil,
+    exec    = nil,
+    ask     = nil,
+    help    = nil,
+}
+
+return M