Add local tokenwar scan

[ousamabenyounes]

Summary

• add tokenwar scan, a local-only log scanner that estimates which TokenWar tools would have helped most
• add an English tool map covering the core stack, strengths, weaknesses, and context-mode alternatives
• document and test the new dispatcher subcommand
• update the complementary-check fixture so it reflects the current six-tool stack (ponytail and pxpipe included)

Test verification (RED -> GREEN)

RED on origin/main with the new dispatcher test applied:

not ok 4 help lists the commands
# `[[ "$output" == *"scan"* ]]` failed

GREEN on this branch, targeted scope plus the fixed check fixture:

$ docker run --rm -v "$PWD:/repo" -w /repo node:20-bookworm bash -lc 'apt-get update >/dev/null && apt-get install -y --no-install-recommends bats shellcheck >/dev/null && shellcheck -S warning scripts/*.sh scripts/lib/*.sh && chmod +x scripts/*.sh && bats tests/check.bats tests/scan.bats tests/dispatcher.bats'
1..12
ok 1 R1 PASS
ok 2 R1 WARN
ok 3 R1 FAIL
ok 4 R2 PASS
ok 5 R3 always PASS
ok 6 Verdict COMPLEMENTARY when all PASS
ok 7 scan recommends shell, context, memory, and code tools from local logs
ok 8 scan json mode emits clients and recommendations
ok 9 dispatcher routes scan subcommand
ok 10 help lists the commands
ok 11 unknown command exits 2 with usage
ok 12 check subcommand runs the checker

Additional validation:

$ bash -n scripts/scan.sh scripts/tokenwar.sh tests/scan.bats tests/dispatcher.bats
$ git diff --check
$ TOKENWAR_SCAN_MAX_FILES=50 TOKENWAR_SCAN_MAX_BYTES_PER_FILE=65536 bash scripts/tokenwar.sh scan --all

Note: a full local Docker bats tests/ run in node:20-bookworm still fails in tests/statusline.bats, but the prior GitHub Actions run on this PR passed those statusline cases. The branch CI is the source of truth for that environment.