Add the GitHub and Gitea steps and split the script into library files

Dry run by default: the script reads from both hosts (tokens, owners,
names, license, SSH) and prints a plan; --apply creates the repositories
and the Gitea -> GitHub push mirror after a final yes. Choosing GitHub
applies the AGPL-3.0 license to the Gitea repository. A failed step is
reported with what exists and how to continue; nothing is ever deleted.

create-project.sh is now the entry point; the work lives in src/lib/, one
responsibility per file. .gitignore gets !src/lib (the Python template
ignores any lib/ folder). Tests grow to 599 checks, with a stub curl and
ssh, and guards for the file structure.

Task: MIL-002#1
Task: MIL-002#2
Task: MIL-002#3
Task: MIL-002#4
Task: MIL-002#5
Task: MIL-002#6
Refs #9
Refs #10
Refs #11
Refs #12
Refs #13
Refs #14

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

tests/run-tests.sh

@@ -23,15 +23,20 @@ failed_checks=0
 
 run_static_checks() {
   printf '== static checks\n'
-  bash -n "$SCRIPT" || failed_checks=$((failed_checks + 1))
+  local file
+  for file in "$SCRIPT" "$SRC_DIR"/lib/*.sh; do
+    bash -n "$file" || failed_checks=$((failed_checks + 1))
+  done
   if command -v shellcheck >/dev/null 2>&1; then
-    shellcheck "$SCRIPT" "$TEST_DIR"/*.sh ||
+    # -x follows the source lines; the library files are named as well,
+    # because shellcheck only reports on the files it is given.
+    shellcheck -x "$SCRIPT" "$SRC_DIR"/lib/*.sh "$TEST_DIR"/*.sh ||
       failed_checks=$((failed_checks + 1))
   else
     printf 'skipped: shellcheck is not installed\n'
   fi
   if command -v shfmt >/dev/null 2>&1; then
-    shfmt -i 2 -ci -d "$SCRIPT" "$TEST_DIR"/*.sh ||
+    shfmt -i 2 -ci -d "$SCRIPT" "$SRC_DIR"/lib/*.sh "$TEST_DIR"/*.sh ||
       failed_checks=$((failed_checks + 1))
   else
     printf 'skipped: shfmt is not installed\n'