feat: initial Zynq XC7Z100 Flasher GUI project

Add cross-platform GUI application for programming Zynq devices
with step-by-step workflow:

- CustomTkinter GUI with dark/light theme support
- 4-step workflow: Check Env → Flash → Bootloader → Main Program
- YAML configuration with relative path resolution
- Serial monitoring and boot log parsing
- TFTP upload with CRC32 verification
- SSH/serial reboot management
- Vivado/Impact tool auto-detection

Project structure:
- app.py: Entry point
- src/: Core modules (config, flash, bitstream, tftp, serial, gui)
- config/: Default configuration template
- .flasher_env/: Python virtual environment

.gitignore

@@ -0,0 +1,40 @@
+# ── Virtual Environment ──────────────────────────────────────
+.flasher_env/
+
+# ── Build/Output ─────────────────────────────────────────────
+dist/
+build/
+*.egg-info/
+*.egg
+
+# ── Python ───────────────────────────────────────────────────
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.pytest_cache/
+.mypy_cache/
+.coverage
+htmlcov/
+.tox/
+.nox/
+
+# ── IDE ──────────────────────────────────────────────────────
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+.DS_Store
+
+# ── Session/Task Tracking ────────────────────────────────────
+.tmp/
+
+# ── Opencode (internal tooling) ──────────────────────────────
+.opencode/
+
+# ── Config overrides (user-specific) ─────────────────────────
+config/zynq_flasher.yaml
+
+# ── Logs ─────────────────────────────────────────────────────
+*.log