Set up repo hygiene — README, CHANGELOG, versioning

README with a maintained key-features section, CHANGELOG.md stub in the
portfolio's IndieAbout format, and a post-build phase stamping
CFBundleVersion (git commit count), BuildDate, and BuildHash into the
app and dSYM Info.plists on every build.

Claude-Session: https://claude.ai/code/session_018BjQRYBR6jQja3jCRi5S3A

project.yml

@@ -19,6 +19,14 @@ targets:
     platform: macOS
     sources:
       - Kanban
+    postBuildScripts:
+      - script: '"${SRCROOT}/../indie-skills/skills/app-versioning/scripts/update_build_info.sh"'
+        name: Update Build Info
+        shell: /bin/sh
+        basedOnDependencyAnalysis: false
+        inputFiles:
+          - $(TARGET_BUILD_DIR)/$(INFOPLIST_PATH)
+          - $(DWARF_DSYM_FOLDER_PATH)/$(DWARF_DSYM_FILE_NAME)/Contents/Info.plist
     settings:
       base:
         PRODUCT_BUNDLE_IDENTIFIER: dev.rzen.indie.Kanban