TradingCodex 0.1.0a7

Changes

• Harden fixed-role subagent dispatch guidance so unverified routing fails closed instead of falling back to generic workers.
• Standardize generated workspace guidance on the local ./tcx wrapper.
• Skip Finder .DS_Store metadata when generating workspaces.
• Bump package version to 0.1.0a7.

Verification

• CI passed on main.
• PyPI publish workflow succeeded for 0.1.0a7.
• PyPI install smoke passed with tcx init and ./tcx doctor.
• install.sh --no-doctor smoke passed with ./tcx doctor.