Phase 4: Macro expansion in compiler

- resolve-macro: resolve symbols to macro vars via ctx
- Macro expansion in analyze-form: detects macro heads, expands, re-analyzes
- compile-ast: emits Janet data structures with resolved core fn values
- compile-and-eval uses compile-ast (no source parse roundtrip)
- eval-string routes macros through compiler (expanded at analyze time)
- Fix - mapping: core-sub (core-- doesn't exist)
- All 317 tests pass + 6 new Phase 4 macro tests

.dirge/memory/PITFALLS.md

@@ -1,5 +1,5 @@
-Janet LSP produces false positives on `.janet` files — it doesn't understand Janet syntax (thinks docstring lines are unresolved symbols, doesn't know `declare-project`/`declare-source` macros, etc.). These are pre-existing and should be ignored — they don't affect runtime correctness.
-§
-Janet `(parse s)` returns `[symbol, error-position]` for forms — e.g., `(parse "(+ 1 2)")` gives `[+ 1]`, not a parsed tuple. For proper evaluation of special forms, must use the parser pipeline: `parser/new` → `parser/consume` → `parser/eof` → `parser/produce` → `eval`. Without `parser/eof`, `produce` returns nil for simple forms like numbers. Janet's `eval` also doesn't support special forms natively in data structures — `(eval [if true 1 2])` fails with "unknown symbol if". Must parse strings, not eval tuples.
+Janet eval scope & source-to-source failure: `(eval '(core-inc 1))` fails with "unknown symbol core-inc" even when the file does `(use ./core)`. Janet's `eval` runs in the default environment and doesn't see `use`-imported symbols. NEVER emit Janet source strings for eval. Instead emit Janet data structures where function VALUES are embedded directly: `[core-inc 1]` not `"(core-inc 1)"`. Use a `core-fn-values` table to resolve names at compile time. The `(parse s)` function returns `[symbol, error-position]` — must use parser pipeline for proper eval: `parser/new→consume→eof→produce→eval`. Without `parser/eof`, numbers/literals return nil from produce. Janet's `eval` also doesn't support special forms natively in data structures — `(eval [if true 1 2])` fails with "unknown symbol if". Must parse strings, not eval tuples.
 §
 When you need to mutate a local with `set`, use `(var x nil)` not `(def x nil)`. `def` creates constants — `(set ns-name ...)` on a `def` fails with "cannot set constant". This hit us in loader.janet ns-name extraction loop.
+§
+core-renames MUST match actual function names defined in core.janet. `"-"` maps to `core-sub` NOT `core--`. `"not"` maps to `core-not` (defined as `(defn core-not ...)`). Missing entries cause silent nil returns. When adding to core-renames, grep core.janet for the actual `(defn core-XXX ...)` or `(def core-XXX ...)` name. Then add matching entry to core-fn-values.