test: expand coverage from 20 to 92 tests, migrate to uv

- Migrate from setuptools to hatchling build backend
- Add dependency-groups (PEP 735) for dev tooling (pytest, ruff)
- Remove redundant requirements.txt in favor of uv.lock
- Fix __version__ mismatch (2.0.0 -> 3.0.0 to match pyproject.toml)

New test files:
- conftest.py: shared fixtures (isolated palace, KG, ChromaDB collection)
- test_knowledge_graph.py: 17 tests (entity CRUD, temporal queries, timeline)
- test_mcp_server.py: 25 tests (protocol dispatch, read/write/KG/diary tools)
- test_searcher.py: 7 tests (search_memories API, filters, error handling)
- test_dialect.py: 13 tests (AAAK compression, entity/emotion detection, zettel encoding)

All 92 tests pass on Python 3.13 with chromadb 0.6.3.

pyproject.toml

@@ -1,7 +1,3 @@
-[build-system]
-requires = ["setuptools>=64"]
-build-backend = "setuptools.build_meta"
-
 [project]
 name = "mempalace"
 version = "3.0.0"
@@ -38,14 +34,18 @@ Homepage = "https://github.com/milla-jovovich/mempalace"
 Repository = "https://github.com/milla-jovovich/mempalace"
 "Bug Tracker" = "https://github.com/milla-jovovich/mempalace/issues"
 
-[tool.setuptools.packages.find]
-include = ["mempalace*"]
-
 [project.scripts]
 mempalace = "mempalace:main"
 
-[project.optional-dependencies]
-dev = ["pytest>=7.0", "build>=1.0", "twine>=4.0"]
+[dependency-groups]
+dev = ["pytest>=7.0", "ruff>=0.4.0"]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["mempalace"]
 
 [tool.ruff]
 line-length = 100