fix(cli): restore unreachable corpus verify command and parsel verify alias

[ra-co88]

Problem

wallbreaker corpus verify [--update] — the interactive surface for the corpus integrity pins in library.lock.toml — is defined but unreachable on main. Running it today does not verify anything: corpus is not in the CLI's subcommand list, so the word is consumed as a one-shot prompt and the TUI starts.

This also breaks the tool's own guidance: wallbreaker/tools/parsel_engine.py:570 tells users to run wallbreaker corpus verify --update when a corpus SHA is unpinned — a command that cannot run.

Root cause

The command was added in 53c9ca2 (roadmap-implementation, TG3): corpus in SUBCOMMANDS, a corpus verify subparser, and its dispatch line. When the PR #21 line merged with the PR #24 (Daedalus) line in da21689, the cli.py conflict resolved to the PR #24 side, which had forked from main before 53c9ca2 and never carried the corpus dispatch. Result: _run_corpus_verify() and _resolve_lock_path() survived as definitions, but their routing, the subparser block, and two imports (subprocess, pathlib.Path) were dropped.

Fix

Restores exactly what the merge dropped (verified against f086481's tree):

• corpus back in SUBCOMMANDS
• the corpus verify subparser (--update, --lock) in build_sub_parser()
• dispatch: corpus → _run_corpus_verify(args), plus the parsel verify alias (verify added to parsel_action choices + getattr routing, matching the function's documented alias)
• re-add import subprocess and from pathlib import Path

The load-time pin check (load_corpus_with_pin_check, fail-closed on mismatch) was always intact and is untouched — this only restores the interactive pin/verify surface.

Regression tests

New tests/test_corpus_cli_routing.py (7 tests) pins the routing so a future merge cannot silently strand the command again:

• parser-level: corpus verify parses (corpus_action == "verify"), with --update/--lock
• "corpus" in SUBCOMMANDS
• main() routing: _run_corpus_verify invoked with the parsed args, return code propagated
• parsel verify alias parses and routes to the same function
• the alias does not swallow the real parsel actions (parsel list still routes to run_parsel_cli)

Plus a CHANGELOG entry under Unreleased.

Test plan

• python -m py_compile wallbreaker/cli.py — clean
• python -m pytest tests/test_corpus_cli_routing.py tests/test_tg3_corpus.py tests/test_cli_one_shot.py -q → 15 passed
• wallbreaker corpus verify --help / wallbreaker corpus verify / wallbreaker corpus verify --update — work as documented (resolves UNRESOLVED pins via git ls-remote; exits non-zero on MISSING/UNRESOLVED as designed)
• wallbreaker parsel verify — alias routes to the same function
• all 12 subcommands parse --help cleanly

Note: an earlier iteration of this branch carried two session_card hardening commits; they were split out to keep this PR focused on the CLI fix.