Refactor as a tree walk

[DannyBen]

This refactors pattern-config completion generation from route-list matching to a command tree walk.

• Builds a tree model from patterns, preserving where option groups and positional tokens appear.
• Generates a compact node-based walker instead of scanning every pattern route.
• Makes option-group placement meaningful, so global options and command-specific options can be modeled separately.
• Stops offering completions after an invalid or out-of-scope option is encountered.
• Keeps numeric node IDs in the generated Bash for compact output, while using clearer node_* naming.
• Updates pattern-config docs, examples, schema examples, and generated-script approvals.