Phase 1: s-expression core library + test infrastructure

S-expression parser, evaluator, and primitive registry in shared/sexp/.
109 unit tests covering parsing, evaluation, special forms, lambdas,
closures, components (defcomp), and 60+ pure builtins.

Test infrastructure: Dockerfile.unit (tier 1, fast) and
Dockerfile.integration (tier 2, ffmpeg). Dev watch mode auto-reruns
on file changes. Deploy gate blocks push on test failure.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/sexp-architecture-plan.md

@@ -598,3 +598,35 @@ rose-ash/
 **Intelligence** (Phases 10-11): Federation makes s-expressions portable across instances. The LLM makes s-expressions accessible to non-programmers — natural language in, rendered pages out. The system learns from its own data, continuously improving the quality of generated s-expressions.
 
 Each phase is independently deployable. The end state: a platform where the application logic is expressed in a small, composable, content-addressed language that humans author, LLMs generate, resolvers execute, IPFS stores, and ActivityPub federates.
+
+---
+
+## Progress Log
+
+### Phase 1: S-Expression Core Library — COMPLETE
+
+**Branch:** `sexpression`
+
+**Delivered** (`shared/sexp/`):
+- `types.py` — Symbol, Keyword, Lambda (callable closure), Component (defcomp), NIL singleton
+- `parser.py` — Tokenizer + parse/parse_all/serialize. Supports lists, vectors, maps, symbols (~component, <>fragment), keywords, strings, numbers, comments, &key/&rest
+- `env.py` — Lexical environment with parent-chain scoping
+- `evaluator.py` — Full evaluator with special forms (if, when, cond, case, and, or, let/let*, lambda/fn, define, defcomp, begin/do, quote, ->, set!) and higher-order forms (map, map-indexed, filter, reduce, some, every?, for-each)
+- `primitives.py` — 60+ pure builtins: arithmetic, comparison, predicates, strings (str, concat, upper, lower, join, split, starts-with?, ends-with?), collections (list, dict, get, first, last, rest, nth, cons, append, keys, vals, merge, assoc, dissoc, into, range, chunk-every, zip-pairs)
+- `__init__.py` — Public API
+
+**Tests** (`shared/sexp/tests/`):
+- `test_parser.py` — 28 tests (atoms, lists, maps, vectors, comments, errors, serialization, roundtrip)
+- `test_evaluator.py` — 81 tests (literals, arithmetic, comparison, predicates, special forms, lambda/closures, collections, higher-order, strings, defcomp, dict literals, set!)
+- **109 tests, all passing**
+
+**Source material ported from:** `artdag/core/artdag/sexp/parser.py` and `evaluator.py`. Stripped DAG-specific types (Binding), replaced Lambda dataclass with callable closure, added defcomp/Component, added web-oriented string primitives, added &key/&rest support in parser.
+
+### Test Infrastructure — COMPLETE
+
+**Delivered:**
+- `test/Dockerfile.unit` — Tier 1: all unit tests (shared + artdag core + L1), pure Python, fast
+- `test/Dockerfile.integration` — Tier 2: integration tests needing ffmpeg/media pipeline
+- `docker-compose.dev.yml` — `test-unit` (watch mode) and `test-integration` services, `profiles: [test]`
+- `dev.sh` — `./dev.sh watch` (auto-rerun on save), `./dev.sh test` (one-shot), `./dev.sh test-integration`
+- `deploy.sh` — Unit test gate: tests must pass before any images are pushed