refactor: comprehensive code quality, security, and release readiness improvements

Security: tighten CORS defaults, add webhook rate limiting, fix XSS in
automations, guard WebSocket JSON.parse, validate ADB address input,
seal debug exception leak, URL-encode WS tokens, CSS.escape in selectors.

Code quality: add Pydantic models for brightness/power endpoints, fix
thread safety and name uniqueness in DeviceStore, immutable update
pattern, split 6 oversized files into 16 focused modules, enable
TypeScript strictNullChecks (741→102 errors), type state variables,
add dom-utils helper, migrate 3 modules from inline onclick to event
delegation, ProcessorDependencies dataclass.

Performance: async store saves, health endpoint log level, command
palette debounce, optimized entity-events comparison, fix service
worker precache list.

Testing: expand from 45 to 293 passing tests — add store tests (141),
route tests (25), core logic tests (42), E2E flow tests (33), organize
into tests/api/, tests/storage/, tests/core/, tests/e2e/.

DevOps: CI test pipeline, pre-commit config, Dockerfile multi-stage
build with non-root user and health check, docker-compose improvements,
version bump to 0.2.0.

Docs: rewrite CLAUDE.md (202→56 lines), server/CLAUDE.md (212→76),
create contexts/server-operations.md, fix .js→.ts references, fix env
var prefix in README, rewrite INSTALLATION.md, add CONTRIBUTING.md and
.env.example.

.pre-commit-config.yaml

@@ -0,0 +1,13 @@
+repos:
+  - repo: https://github.com/psf/black
+    rev: '24.10.0'
+    hooks:
+      - id: black
+        args: [--line-length=100, --target-version=py311]
+        language_version: python3.11
+
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.8.0
+    hooks:
+      - id: ruff
+        args: [--line-length=100, --target-version=py311]