chore: block all team-docs/ from main and preview (no exceptions) #50

What

Update the guard workflow (\squad-main-guard.yml) so that nothing in \ eam-docs/\ ever reaches \main\ or \preview\ — no exceptions. Currently \ eam-docs/blog/\ is allowed through, but once blogs move to \docs/blog/\ (see #49), there's no reason for any \ eam-docs/\ content on protected branches.

Why

• \ eam-docs/\ is internal team state — proposals, sprint plans, working notes
• Blogs are moving to \docs/blog/\ (chore: move blogs from team-docs/blog to docs/blog, enforce naming convention #49), so the \ eam-docs/blog/\ exception becomes unnecessary
• Simpler guard rule: \ eam-docs/**\ → blocked, period

Acceptance Criteria

• Guard workflow blocks ALL \ eam-docs/\ paths (remove \ eam-docs/blog/\ exception)
• Template copy (\ emplates/workflows/squad-main-guard.yml) updated to match
• Guard error message updated to remove blog exception language
• \CONTRIBUTING.md\ updated to reflect that \ eam-docs/\ is fully blocked (no exceptions)
• Depends on chore: move blogs from team-docs/blog to docs/blog, enforce naming convention #49 (blogs must be moved first)

Dependencies

Blocked by #49 — blogs must move to \docs/blog/\ before we can remove the \ eam-docs/blog/\ exception.