add Flutter-rebuild project identity at the repo root

project.yaml is fresh and declares version 2.0.0-dev — a clean break
from Python clide's v1.2.0 (which remains under legacy/). It carries
module path, toolchain pins (go >=1.25, Flutter stable, Dart >=3.5),
and the Gitea repository URL. Same schema as the Makefile will read
via awk for sidecar version stamping.

README.md and LICENSE land alongside. The README pitches the rebuild
tersely and points at docs/initial-plan.md for the full story; the
Python README is preserved under legacy/README.md.

.gitignore is rewritten for the new toolchain. The previous file was
wall-to-wall Python rules; now the root ignores Flutter/Dart/Go build
output plus the usual OS/editor/secrets/.claude-local entries, and
Python-specific rules scope to legacy/** so they don't fire on any
stray caches at the repo root.

.editorconfig sets tabs for Go, two-space for Dart and everything
else, and the usual EOL + trailing-whitespace rules.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.editorconfig

@@ -0,0 +1,22 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+[*.go]
+indent_style = tab
+indent_size = 4
+
+[*.dart]
+indent_size = 2
+
+[Makefile]
+indent_style = tab
+
+[*.md]
+trim_trailing_whitespace = false