refactor(llm): 拆分提示词与提交解析逻辑到独立模块

将 21 个多语言提示词及选择函数迁入 prompts 模块，将 commit 响应
解析与 GeneratedCommit 迁入 parsing 模块，为 rig 迁移期间新旧
实现共享同一份提示词与解析逻辑做准备。无行为变化。

src/llm/parsing.rs

@@ -0,0 +1,281 @@
+use anyhow::{Result, bail};
+
+/// Parse commit response from LLM
+pub(crate) fn parse_commit_response(
+    response: &str,
+    format: crate::config::CommitFormat,
+) -> Result<GeneratedCommit> {
+    // Clean markdown code fences from the response
+    let cleaned = strip_code_fences(response);
+
+    let lines: Vec<&str> = cleaned
+        .lines()
+        .map(|l| l.trim())
+        .filter(|l| !l.is_empty())
+        .collect();
+
+    if lines.is_empty() {
+        let preview: String = response.chars().take(200).collect();
+        bail!(
+            "LLM returned empty or whitespace-only response. \
+             Raw response preview: '{}'. \
+             Hint: If using DeepSeek/Kimi with thinking enabled, \
+             the model may have returned reasoning_content only. \
+             Try disabling thinking mode or switching models.",
+            preview
+        );
+    }
+
+    // Find the line most likely to be the commit subject
+    let first_line = find_commit_subject_line(&lines, format);
+
+    // Parse based on format
+    match format {
+        crate::config::CommitFormat::Conventional => {
+            parse_conventional_commit(first_line, &lines, response)
+        }
+        crate::config::CommitFormat::Commitlint => {
+            parse_commitlint_commit(first_line, &lines, response)
+        }
+    }
+}
+
+/// Remove surrounding markdown code fences (```) from LLM output
+fn strip_code_fences(response: &str) -> String {
+    let mut lines: Vec<&str> = response.lines().collect();
+
+    // Strip leading fence lines (``` or ```lang)
+    while lines.first().map_or(false, |l| l.trim().starts_with("```")) {
+        lines.remove(0);
+    }
+
+    // Strip trailing fence lines
+    while lines.last().map_or(false, |l| l.trim() == "```") {
+        lines.pop();
+    }
+
+    lines.join("\n")
+}
+
+/// Find the line that is most likely the commit subject among extracted lines
+fn find_commit_subject_line<'a>(
+    lines: &[&'a str],
+    format: crate::config::CommitFormat,
+) -> &'a str {
+    let valid_types = crate::utils::validators::get_commit_types(matches!(
+        format,
+        crate::config::CommitFormat::Commitlint
+    ));
+
+    // First pass: line starting with a known type that also has proper syntax
+    // (e.g. "type:", "type(scope):", "type!:")
+    for &line in lines {
+        let trimmed = line.trim();
+        for &t in valid_types {
+            if let Some(rest) = trimmed.strip_prefix(t) {
+                if rest.starts_with(':') || rest.starts_with('(') || rest.starts_with("!:") {
+                    return trimmed;
+                }
+            }
+        }
+    }
+
+    // Second pass: any line containing a colon (generic "prefix: description")
+    for &line in lines {
+        if line.contains(':') {
+            return line.trim();
+        }
+    }
+
+    // Fallback: return the first line as-is
+    lines[0].trim()
+}
+
+fn parse_conventional_commit(
+    first_line: &str,
+    lines: &[&str],
+    raw_response: &str,
+) -> Result<GeneratedCommit> {
+    // Parse: type(scope)!: description
+    let parts: Vec<&str> = first_line.splitn(2, ':').collect();
+    if parts.len() != 2 {
+        let preview: String = raw_response.chars().take(300).collect();
+        bail!(
+            "Invalid conventional commit format: missing colon.\n\
+             Parsed subject line: '{}'\n\
+             Raw response preview: '{}'\n\
+             Expected: <type>[optional scope]: <description>",
+            first_line,
+            preview
+        );
+    }
+
+    let type_part = parts[0];
+    let description = parts[1].trim();
+
+    // Extract type, scope, and breaking indicator
+    let breaking = type_part.ends_with('!');
+    let type_part = type_part.trim_end_matches('!');
+
+    let (commit_type, scope) = if let Some(start) = type_part.find('(') {
+        if let Some(end) = type_part.find(')') {
+            let t = &type_part[..start];
+            let s = &type_part[start + 1..end];
+            (t.to_string(), Some(s.to_string()))
+        } else {
+            bail!("Invalid scope format: missing closing parenthesis");
+        }
+    } else {
+        (type_part.to_string(), None)
+    };
+
+    // Extract body and footer
+    let (body, footer) = extract_body_footer(lines);
+
+    Ok(GeneratedCommit {
+        commit_type,
+        scope,
+        description: description.to_string(),
+        body,
+        footer,
+        breaking,
+    })
+}
+
+fn parse_commitlint_commit(
+    first_line: &str,
+    lines: &[&str],
+    raw_response: &str,
+) -> Result<GeneratedCommit> {
+    // Similar parsing but with commitlint rules
+    let parts: Vec<&str> = first_line.splitn(2, ':').collect();
+    if parts.len() != 2 {
+        let preview: String = raw_response.chars().take(300).collect();
+        bail!(
+            "Invalid commit format: missing colon.\n\
+             Parsed subject line: '{}'\n\
+             Raw response preview: '{}'\n\
+             Expected: <type>[optional scope]: <subject>",
+            first_line,
+            preview
+        );
+    }
+
+    let type_part = parts[0];
+    let subject = parts[1].trim();
+
+    let (commit_type, scope) = if let Some(start) = type_part.find('(') {
+        if let Some(end) = type_part.find(')') {
+            let t = &type_part[..start];
+            let s = &type_part[start + 1..end];
+            (t.to_string(), Some(s.to_string()))
+        } else {
+            (type_part.to_string(), None)
+        }
+    } else {
+        (type_part.to_string(), None)
+    };
+
+    let (body, footer) = extract_body_footer(&lines);
+
+    Ok(GeneratedCommit {
+        commit_type,
+        scope,
+        description: subject.to_string(),
+        body,
+        footer,
+        breaking: false,
+    })
+}
+
+fn extract_body_footer(lines: &[&str]) -> (Option<String>, Option<String>) {
+    if lines.len() <= 1 {
+        return (None, None);
+    }
+
+    let rest: Vec<&str> = lines[1..]
+        .iter()
+        .skip_while(|l| l.trim().is_empty())
+        .copied()
+        .collect();
+
+    if rest.is_empty() {
+        return (None, None);
+    }
+
+    // Look for footer markers
+    let footer_markers = [
+        "BREAKING CHANGE:",
+        "Closes",
+        "Fixes",
+        "Refs",
+        "Co-authored-by:",
+    ];
+
+    let mut body_lines = vec![];
+    let mut footer_lines = vec![];
+    let mut in_footer = false;
+
+    for line in &rest {
+        if footer_markers.iter().any(|m| line.starts_with(m)) {
+            in_footer = true;
+        }
+
+        if in_footer {
+            footer_lines.push(*line);
+        } else {
+            body_lines.push(*line);
+        }
+    }
+
+    let body = if body_lines.is_empty() {
+        None
+    } else {
+        Some(body_lines.join("\n"))
+    };
+
+    let footer = if footer_lines.is_empty() {
+        None
+    } else {
+        Some(footer_lines.join("\n"))
+    };
+
+    (body, footer)
+}
+
+/// Generated commit structure
+#[derive(Debug, Clone)]
+pub struct GeneratedCommit {
+    pub commit_type: String,
+    pub scope: Option<String>,
+    pub description: String,
+    pub body: Option<String>,
+    pub footer: Option<String>,
+    pub breaking: bool,
+}
+
+impl GeneratedCommit {
+    /// Format as conventional commit
+    pub fn to_conventional(&self) -> String {
+        crate::utils::formatter::format_conventional_commit(
+            &self.commit_type,
+            self.scope.as_deref(),
+            &self.description,
+            self.body.as_deref(),
+            self.footer.as_deref(),
+            self.breaking,
+        )
+    }
+
+    /// Format as commitlint commit
+    pub fn to_commitlint(&self) -> String {
+        crate::utils::formatter::format_commitlint_commit(
+            &self.commit_type,
+            self.scope.as_deref(),
+            &self.description,
+            self.body.as_deref(),
+            self.footer.as_deref(),
+            None,
+        )
+    }
+}