Modified a few things:

- Finished implementing relative date parsing and migrated date parsing
  from Flag(T) to it's own dedicated module. Additionally added a
  the ability to do "recursive" relative operations for time searching.
- Additionally made a Struct & Enum for containing relative operations
  around dates.
- Added additional checks in App & CommandNode(T) around checking
  env_vars of flags & checking for duplicate commands
- Added a CommandMeta record to contain the classname of the
  CommandNode(T)
- Seperated out all of the monolitic files (command_node.cr & file.cr).
  Moved the base classes and records into their own files in the dir
  with the same name of their generic counterparts.
- Fixed a number of macro related bugs around Command.argument &
  CliGen.add_global_flag
- My ass hurts from sitting here for hours and doing these changes and
  arguing with claude over what needs to be done. Fun tho.

utils/flag_matrix.sh

@@ -0,0 +1,87 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2026 Tristan Ancelet
+#
+# Runs flag_matrix.cr across every value source (default / env / CLI) for both
+# a global flag and a command argument, and checks each result.
+#
+# Each case needs its own process because env vars must be set before startup,
+# which is why this lives here rather than in spec/.
+#
+#   ./utils/flag_matrix.sh      (runnable from anywhere)
+#
+# Exits non-zero if any case does not match.
+
+set -u
+
+# Build from the PROJECT ROOT, not utils/. Two things depend on the CWD:
+#   - `require "cligen"` resolves via ./lib/cligen (the self-symlink)
+#   - command_node.cr renders ECR from the hardcoded relative path
+#     "lib/cligen/src/cligen/template/cmd_help.ecr"
+# Building inside utils/ breaks both.
+cd "$(dirname "$0")/.."
+
+SRC=utils/flag_matrix.cr
+BIN=utils/flag_matrix
+pass=0
+fail=0
+
+echo "building..."
+if ! crystal build "$SRC" -o "$BIN" 2>&1 | grep -v sframe; then :; fi
+[ -x "$BIN" ] || { echo "build failed"; exit 1; }
+echo
+
+# check <label> <expected-substring> <env-assignments> <args...>
+#
+# Matches against the FULL output, not just the last line - multi-line output
+# such as help text would otherwise only ever be compared against its footer.
+# Only the last line is echoed back, to keep the report readable.
+check() {
+  local label="$1" want="$2" envs="$3"; shift 3
+  local got shown
+  got=$(env $envs "$BIN" "$@" 2>&1)
+  shown=$(printf '%s' "$got" | tail -1)
+  if [[ "$got" == *"$want"* ]]; then
+    printf '  ok   %-44s %s\n' "$label" "$shown"
+    pass=$((pass + 1))
+  else
+    printf '  FAIL %-44s %s\n' "$label" "$shown"
+    printf '       %-44s want substring: %s\n' "" "$want"
+    fail=$((fail + 1))
+  fi
+}
+
+echo "== defaults =="
+check "no env, no flags"            "retries=3 level=1 name=world" "" greet
+
+echo
+echo "== global flag: --retries (env RETRIES, valid 0..10) =="
+check "env valid"                   "retries=7"                    "RETRIES=7"  greet
+check "env invalid -> rejected"     "validation failed for --retries" "RETRIES=99" greet
+check "cli valid"                   "retries=5"                    ""           greet -r 5
+check "cli invalid -> rejected"     "validation failed for --retries" ""         greet -r 99
+check "cli overrides env"           "retries=2"                    "RETRIES=8"  greet -r 2
+
+echo
+echo "== command arg: --level (env GREET_LEVEL, valid < 5) =="
+check "env valid"                   "level=3"                      "GREET_LEVEL=3" greet
+check "env invalid -> rejected"     "validation failed for --level" "GREET_LEVEL=9" greet
+check "cli valid"                   "level=4"                      ""              greet --level 4
+check "cli invalid -> rejected"     "validation failed for --level" ""              greet --level 9
+check "cli overrides env"           "level=2"                      "GREET_LEVEL=4" greet --level 2
+check "un-namespaced LEVEL ignored" "level=1"                      "LEVEL=9"       greet
+
+echo
+echo "== command arg: --name (no validation) =="
+check "env"                         "name=Bob"                     "GREET_NAME=Bob" greet
+check "cli"                         "name=Alice"                   ""               greet --name Alice
+
+echo
+echo "== help output =="
+check "root help lists globals"     "--retries"                    ""  --help
+check "command help lists args"     "--level"                      ""  greet --help
+
+echo
+echo "$pass passed, $fail failed"
+rm -f "$BIN"
+[ "$fail" -eq 0 ]