Add the RepoFoundry foundation: config parsing, HTTP helper, prompts, tests

create-project.sh validates config.env and .env (parsed, never sourced),
checks the required tools, asks for the project details and prints a
summary. It makes no network call and no change on disk yet.

- config.env.example and .env.example hold placeholders only
- tokens go through a private curl config file, never the command line
- tests run in private directories with a stub curl; shellcheck and shfmt
  are part of tests/run-tests.sh

Task: MIL-001#1
Task: MIL-001#2
Task: MIL-001#3
Task: MIL-001#4
Task: MIL-001#5
Task: MIL-001#6
Closes #3
Closes #4
Closes #5
Closes #6
Closes #7
Closes #8

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

.gitignore

@@ -174,3 +174,13 @@ cython_debug/
 # PyPI configuration file
 .pypirc
 
+
+# RepoFoundry: credentials and temporary files
+.env
+.env.*
+!.env.example
+*.tmp
+*.swp
+*~
+tmp/
+repofoundry.*/