fix: 修复 tag/changelog 生成范围，增加 --auto 模式

- fix(get_tags): 使用 find_object+peel_to_commit 支持 annotated tag
- fix(changelog): insert_changelog_entry 替换覆盖逻辑，保留已有章节
- feat: parse_changelog_versions 按 semver 降序提取版本
- feat: sort_tags_by_semver 取代纯时间排序
- feat(tag --auto): 优先读 Cargo.toml/pyproject.toml，回退 commit 分析
- feat(changelog): 无 --from 时自动检测 changelog 最高已有版本
- refactor: TagInfo::version_name(), GitRepo::find_tag_by_version()

src/commands/tag.rs

@@ -8,7 +8,8 @@ use std::path::PathBuf;
 use crate::config::{Language, manager::ConfigManager};
 use crate::generator::ContentGenerator;
 use crate::git::tag::{
-    TagBuilder, VersionBump, bump_version, get_latest_version, suggest_version_bump,
+    TagBuilder, VersionBump, bump_version, get_latest_version, read_project_version,
+    suggest_version_bump,
 };
 use crate::git::{GitRepo, find_repo};
 use crate::i18n::Messages;
@@ -63,6 +64,11 @@ pub struct TagCommand {
     /// Skip interactive prompts
     #[arg(short = 'y', long)]
     yes: bool,
+
+    /// Auto-detect version from project config (Cargo.toml/pyproject.toml),
+    /// falling back to commit analysis with confirmation. Mutually exclusive with --bump.
+    #[arg(short = 'A', long, conflicts_with = "bump")]
+    auto: bool,
 }
 
 impl TagCommand {
@@ -80,6 +86,9 @@ impl TagCommand {
         // Determine tag name
         let tag_name = if let Some(name) = &self.name {
             name.clone()
+        } else if self.auto {
+            self.auto_detect_version(&repo, &config.tag.version_prefix, &messages)
+                .await?
         } else if let Some(bump_str) = &self.bump {
             // Calculate bumped version
             let prefix = &config.tag.version_prefix;
@@ -325,6 +334,57 @@ impl TagCommand {
             .await
     }
 
+    async fn auto_detect_version(
+        &self,
+        repo: &GitRepo,
+        prefix: &str,
+        messages: &Messages,
+    ) -> Result<String> {
+        let project_dir = std::env::current_dir()?;
+
+        // 1. Try reading from project config files
+        if let Some(version) = read_project_version(&project_dir) {
+            let tag_name = format!("{}{}", prefix, version);
+            println!(
+                "{} {}",
+                messages.latest_version(),
+                tag_name.cyan()
+            );
+            return Ok(tag_name);
+        }
+
+        // 2. Fall back to commit analysis
+        println!("{}", messages.auto_detect_bump());
+        let commits = repo.get_commits(50)?;
+        let bump = suggest_version_bump(&commits);
+        let latest = get_latest_version(repo, prefix)?.unwrap_or_else(|| Version::new(0, 0, 0));
+        let version = bump_version(&latest, bump, None);
+        let tag_name = format!("{}{}", prefix, version);
+
+        println!(
+            "{} {:?} → {}",
+            messages.suggested_bump(),
+            bump,
+            tag_name.cyan()
+        );
+
+        if !self.yes {
+            let confirm = Confirm::new()
+                .with_prompt(messages.use_this_version())
+                .default(true)
+                .interact()?;
+
+            if !confirm {
+                // Fall through to interactive version selection
+                return self
+                    .select_version_interactive(repo, prefix, messages)
+                    .await;
+            }
+        }
+
+        Ok(tag_name)
+    }
+
     fn input_message_interactive(&self, version: &str, messages: &Messages) -> Result<String> {
         let default_msg = format!("Release {}", version);