docs: add agent skill guides and update CMake build instructions

.agents/rules/micromamba_build.md

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+---
+trigger: always_on
+---
+
+# Rule: Build uLib with Micromamba
+
+This rule provides instructions for building the uLib project using the micromamba environment.
+
+## Context
+- **Environment**: micromamba `uLib`
+- **Output Directory**: `build`
+- **CPU Usage**: All available cores
+
+## Instructions
+
+1. **Environment Setup**:
+   Ensure micromamba is properly initialized and the `uLib` environment is active.
+   ```bash
+   export MAMBA_EXE="/home/share/micromamba/bin/micromamba"
+   export MAMBA_ROOT_PREFIX="/home/share/micromamba"
+   export PRESET="clang-make"
+   eval "$(${MAMBA_EXE} shell hook --shell bash)"
+   micromamba activate uLib
+   ```
+
+2. **Full Rebuild (if needed)**:
+   If the `build` directory does not exist or a full reconfiguration is required:
+   ```bash
+   conan install . --output-folder=build/${PRESET} --build=missing --profile=fast
+   cmake --preset ${PRESET}
+   cmake --build build/${PRESET} -j$(nproc)
+   ```
+
+3. **Incremental Build**:
+   Run the build command from the root directory, pointing to the `build` folder and using all cores.
+   ```bash
+   cmake --build build/${PRESET} -j$(nproc)
+   ```
+
+4. **Specific Target Build - gcompose**:
+   To build a specific target (e.g., gcompose):
+   ```bash
+   cmake --build build/${PRESET} --target gcompose -j$(nproc)
+   ```