Adopt component log categories and deprecate VERBOSE

[codeforester]

Problem

Reusable base-bash-libs modules currently emit records through the default
logger. A caller that selects DEBUG for its own diagnostics therefore has no
stable way to keep library diagnostics at INFO unless every library record is
assigned a component category.

The library also exposes a Bash-specific VERBOSE level and log_verbose*
helpers. There are no production callers in the Base repositories, and
non-Bash wrappers already collapse --verbose-wrapper to the same
LOG_DEBUG=1 contract as --debug-wrapper.

Goal

Adopt component categories throughout the reusable library and begin a
compatibility-safe deprecation of the extra VERBOSE surface.

Dependency

• Depends on Add hierarchical log-category gates and enabled checks #187, which adds the category gate and log_is_enabled contract.

Scope

• Assign every internal library log call to one of these categories:
  • base_bash_libs.std
  • base_bash_libs.arg
  • base_bash_libs.file
  • base_bash_libs.git
  • base_bash_libs.gh
• Initialize the parent base_bash_libs category at INFO so a caller's DEBUG
  terminal setting does not implicitly enable reusable-library DEBUG records.
• Preserve explicit opt-in:
  • --debug-wrapper enables DEBUG terminal output and the
    base_bash_libs DEBUG category.
  • --verbose-wrapper preserves its current terminal and library-category
    behavior during the deprecation window.
• Mark these compatibility surfaces deprecated in documentation and source
  comments without emitting runtime warnings:
  • the VERBOSE level;
  • log_verbose and log_verbose_file;
  • log_verbose_enter and log_verbose_leave;
  • --verbose-wrapper.
• Keep all deprecated symbols and their current behavior in the 1.x line.
• Document how applications can independently configure caller and reusable
  library diagnostics.
• Add a changelog entry and focused regression coverage.

Acceptance criteria

• A caller using DEBUG while base_bash_libs remains at its default INFO gate
  does not receive library DEBUG records.
• Enabling base_bash_libs=DEBUG enables DEBUG records for every library
  component.
• A child override such as base_bash_libs.git=DEBUG enables only that
  component when the parent remains at INFO.
• Every production severity call in the reusable modules has a component
  category.
• --debug-wrapper continues to expose command-line and library DEBUG output.
• Existing VERBOSE calls and --verbose-wrapper retain their exact runtime
  behavior.
• Deprecation documentation identifies the next major release as the earliest
  removal point.
• Focused BATS tests and the complete repository validation pass.

Non-goals

• Removing or aliasing the VERBOSE level in this change.
• Emitting deprecation warnings at runtime.
• Deprecating basectl --verbose-wrapper; that belongs to a separate Base
  issue/PR after this library train is available.
• Changing rendered log-record formatting.
• Changing VERSION or publishing a release.

Validation

• Focused logging tests in lib/bash/std/tests/lib_std.bats.
• Module-level category coverage, including
  lib/bash/git/tests/lib_git.bats.
• Wrapper/launcher compatibility coverage.
• ./tests/validate.sh
• git diff --check

[codeforester]

Implementation is in draft PR #190, stacked on the category API in #189. Because the PR currently targets the train branch rather than main, GitHub will activate its Closes #188 link when the PR is retargeted after #189 merges.