feat: add initial project structure with spam detection tool and supporting libraries

Add the complete source tree for the isspam spam detection utility, including the main C implementation (isspam.c), custom memory allocator (rmalloc.h), string builder (rstr.h), dynamic string list (rstring_list.h), build configuration (Makefile, .clang-format), CI workflow (.gitea/workflows/build.yaml), and sample test data (spam/examole_spam3.txt, not_spam/correct1.txt). The core logic defines a list of forbidden words and provides functions for tokenizing input, removing preserved characters, and checking content against the spam keyword set.

.gitea/workflows/build.yaml

@@ -0,0 +1,16 @@
+name: isspam build
+run-name: isspam build and memory check
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - run: apt update
+      - run: apt install build-essential valgrind make -y
+      - name: Check out repository code
+        uses: actions/checkout@v4
+      - name: List files in the repository
+        run: |
+          ls ${{ gitea.workspace }}
+      - run: make valgrind