flagspec_reject() now names a likely-intended flag when an unrecognized
flag closely matches exactly one entry in the descriptor table (genuine
Levenshtein DP, silent on zero or ambiguous matches). flagspec_render_help()
generates the short/long/required-optional/default flag-listing block from
a descriptor table. 1278/1278 controller suite passing (+5).
Task 1.2 of .kiro/specs/xce-test-cli-ux/tasks.md.
Requirements: 6.1, 6.2, 6.3, 6.4, 8.2, 10.1, 10.2, 10.3
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019jaMf9QEwpugH2W9KAuc7f
Adds flagspec_t descriptor table, getopt_long option-table builder, and
the shared stderr-routed rejection path that every flag-accepting
command will migrate onto in later tasks. TDD'd via test_flagspec.c
(1273/1273 controller suite passing).
Task 1.1 of .kiro/specs/xce-test-cli-ux/tasks.md.
Requirements: 2.1, 2.2, 2.3, 2.4, 3.1
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019jaMf9QEwpugH2W9KAuc7f
