fix(docs): correct bd dep add syntax and semantics

Fixed incorrect bd dep documentation in prime.go, cursor.go, and aider.go

- Added missing 'add' subcommand (was 'bd dep <from> <to>', now 'bd dep add <issue> <depends-on>')
- Corrected semantics (docs claimed 'from blocks to' but actual behavior is 'issue depends on depends-on')

This fixes AI agents and users consistently creating dependencies in the wrong direction.

Co-authored-by: jflam <jflam@users.noreply.github.com>

cmd/bd/setup/aider.go

@@ -33,7 +33,7 @@ This project uses **Beads (bd)** for issue tracking. Aider requires explicit com
 - ` + "`bd create --title=\"...\" --type=task`" + ` - Create new issue
 - ` + "`bd update <id> --status=in_progress`" + ` - Claim work
 - ` + "`bd close <id>`" + ` - Mark complete
-- ` + "`bd dep <from> <to>`" + ` - Add dependency (from blocks to)
+- ` + "`bd dep add <issue> <depends-on>`" + ` - Add dependency (issue depends on depends-on)
 - ` + "`bd sync`" + ` - Sync with git remote
 
 ## Workflow Pattern to Suggest

cmd/bd/setup/cursor.go

@@ -27,7 +27,7 @@ bd list --status=open                 # List all open issues
 bd create --title="..." --type=task  # Create new issue
 bd update <id> --status=in_progress  # Claim work
 bd close <id>                         # Mark complete
-bd dep <from> <to>                    # Add dependency (from blocks to)
+bd dep add <issue> <depends-on>       # Add dependency (issue depends on depends-on)
 bd sync                               # Sync with git remote
 ` + "```" + `