meme public API: read and print meme syntax.

Three tracks:
  text-to-form:  meme->forms, forms->meme (all platforms)
  form-to-text:  forms->clj (all platforms), clj->forms (JVM only)
  text-to-text:  meme->clj (all platforms), clj->meme (JVM only)

Pipeline:
  meme.alpha.pipeline/run — full ctx->ctx pipeline with intermediate state

Pretty-printer: Clojure forms → idiomatic multi-line meme text.
Width-aware — uses indented parenthesized form for multi-line calls.

meme printer: Clojure forms → meme text.

Consistent error infrastructure for the meme reader/tokenizer.
All error throw sites should use `meme-error` to ensure uniform
location tracking and message formatting.

Shared form-level predicates and constructors.
Cross-stage contracts that both the parser and printer depend on.

meme reader: recursive-descent parser.
Transforms meme tokens into Clojure forms.

Value resolution: converts raw token text to Clojure values.
All resolution is native — no delegation to read-string.

Explicit pipeline composition: source → scan → group → parse → resolve → forms.
Each stage is a ctx -> ctx function operating on a shared context map.

Unified CLI. Functions accept a map — works with both clj -T and bb.

meme REPL: read meme, eval as Clojure, print result.

Run .meme files: read, eval, return last result.

Token grouping stage: pass-through (all forms are now parsed natively
by the recursive-descent parser). Retained for pipeline symmetry.

Scanner-level source-position utilities.
Defines the character-level line/col model used by the tokenizer and grouper.
Only \n advances the line counter — \r is a regular character that occupies
a column. This matches sadvance! in the tokenizer.

Note: this is the *scanner* line model, not a universal line definition.
The error display module (meme.alpha.errors/source-context) uses
str/split-lines which has different line-ending semantics (splits on
both \n and \r\n). The two models agree for LF sources but diverge
for CRLF. See format-error for how the bridge is handled.

meme tokenizer: character scanning and token production.
Transforms meme source text into a flat vector of typed tokens.