[Input] Support arch/ and ext/ directories alongside app/

[TrueNine]

Bug Description

Need to support reading from arch/ and ext/ directories in addition to existing app/ directory.

Current Behavior

• Only app/ directory is supported for reading source projects
• Output target is workspace/<project>

Expected Behavior

Support three directories with identical functionality but different semantics:

Directory	Purpose
app/	Currently maintained projects
arch/	Archived projects (no longer actively maintained)
ext/	External projects (temporary projects for forks, PRs, issues, etc.)

• All three should work the same way as app/
• Read source from shadow source project/ext|arch
• Output to workspace/<project>

Example Use Cases

• arch/: Old versions of projects, deprecated tools, historical code
• ext/: Forking others' projects to submit PRs, issue tracking repos, temporary work

Additional Context

• Context: CLI (tnmsc)
• Related to input plugin / shadow project handling