feat(releaser): add --verbose flag for configuration and decision tracing

- Prints a configuration table on startup showing each key, its value,
  and the source (default / config file / env: VARNAME / flag: --name)
- Lists every commit since the last tag with its parsed type and
  the version-bump decision (feat/fix/breaking → patch bump, or ignored)
- Explains the final version choice: highest commit type → next tag
- All verbose output goes to stderr so it never pollutes stdout captures
- Sources tracking wired through config.LoadWithSources and
  ApplyEnvWithSources; LoadWithSources uses a two-pass approach to
  detect which YAML fields were explicitly set vs defaulted

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -1,6 +1,6 @@
 # releaser
 
-![release](https://img.shields.io/badge/release-v1.1.0-blue.svg)
+![release](https://img.shields.io/badge/release-v1.1.1-blue.svg)
 
 A CI-friendly release automation tool for GitFlow workflows using Conventional Commits.
 
@@ -64,6 +64,9 @@ releaser --branch release/1.2
 # Write changelog to a custom file
 releaser --changelog-file CHANGES.md
 
+# Show configuration sources, commit list, and version decision
+releaser --verbose --dry-run
+
 # Target a specific pom.xml
 releaser --pom path/to/pom.xml