feat: add git collector using agent-analyzer binary

New git collector in lib/collectors/ that runs agent-analyzer git-map
init and extracts health, hotspots, contributors, AI ratio, bus factor,
conventions, and release info. Registered in collect() dispatch.

Author: avifenesh

lib/collectors/git.js

@@ -0,0 +1,143 @@
+/**
+ * Git History Collector
+ *
+ * Collects git history analysis data using the agent-analyzer binary.
+ * Runs a full git-map init and extracts key metrics for downstream consumers.
+ *
+ * @module lib/collectors/git
+ */
+
+'use strict';
+
+const binary = require('../binary');
+
+const DEFAULT_OPTIONS = {
+  top: 20,
+  adjustForAi: false,
+  cwd: process.cwd()
+};
+
+/**
+ * Collect git history data for the given repository.
+ *
+ * Runs agent-analyzer git-map init to produce a full map, then extracts
+ * key metrics (hotspots, bus factor, AI ratio, etc.) from the result.
+ *
+ * @param {Object} [options={}] - Collection options
+ * @param {string} [options.cwd] - Repository path (default: process.cwd())
+ * @param {number} [options.top=20] - Number of hotspots to return
+ * @param {boolean} [options.adjustForAi=false] - Adjust bus factor for AI commits
+ * @returns {Object} Git history metrics
+ */
+function collectGitData(options = {}) {
+  const opts = { ...DEFAULT_OPTIONS, ...options };
+  const cwd = opts.cwd || process.cwd();
+
+  try {
+    binary.ensureBinarySync();
+  } catch (err) {
+    return {
+      available: false,
+      error: `Binary not available: ${err.message}`
+    };
+  }
+
+  let map;
+  try {
+    const json = binary.runAnalyzer(['git-map', 'init', cwd]);
+    map = JSON.parse(json);
+  } catch (err) {
+    return {
+      available: false,
+      error: `Git analysis failed: ${err.message}`
+    };
+  }
+
+  // Extract metrics from the map
+  const fileActivity = map.fileActivity || {};
+  const contributors = map.contributors || {};
+  const aiAttribution = map.aiAttribution || {};
+  const commitShape = map.commitShape || {};
+  const conventions = map.conventions || {};
+  const releases = map.releases || {};
+
+  // Hotspots: sort files by change count
+  const hotspots = Object.entries(fileActivity)
+    .map(([path, activity]) => ({
+      path,
+      changes: activity.totalChanges || 0,
+      authors: activity.authors ? Object.keys(activity.authors).length : 0,
+      lastChanged: activity.lastChanged || null
+    }))
+    .sort((a, b) => b.changes - a.changes)
+    .slice(0, opts.top);
+
+  // Contributors summary
+  const humans = contributors.humans || {};
+  const humanList = Object.entries(humans)
+    .map(([name, data]) => ({
+      name,
+      commits: data.commitCount || 0,
+      firstSeen: data.firstSeen || null,
+      lastSeen: data.lastSeen || null
+    }))
+    .sort((a, b) => b.commits - a.commits);
+
+  // Bus factor: people covering 80% of commits
+  const totalCommits = humanList.reduce((sum, c) => sum + c.commits, 0);
+  let cumulative = 0;
+  let busFactor = 0;
+  for (const contributor of humanList) {
+    cumulative += contributor.commits;
+    busFactor++;
+    if (cumulative >= totalCommits * 0.8) break;
+  }
+
+  // AI ratio
+  const aiTotal = (aiAttribution.attributed || 0) + (aiAttribution.heuristic || 0);
+  const allCommits = map.git?.totalCommitsAnalyzed || totalCommits;
+  const aiRatio = allCommits > 0 ? aiTotal / allCommits : 0;
+
+  return {
+    available: true,
+    health: {
+      active: humanList.length > 0,
+      busFactor,
+      aiRatio: Math.round(aiRatio * 100) / 100,
+      totalCommits: allCommits,
+      totalContributors: humanList.length
+    },
+    hotspots,
+    contributors: humanList.slice(0, 10),
+    aiAttribution: {
+      ratio: Math.round(aiRatio * 100) / 100,
+      attributed: aiAttribution.attributed || 0,
+      heuristic: aiAttribution.heuristic || 0,
+      none: aiAttribution.none || 0,
+      tools: aiAttribution.tools || {}
+    },
+    busFactor,
+    conventions: {
+      style: conventions.style || null,
+      prefixes: conventions.prefixes || {},
+      scopes: conventions.scopes || {}
+    },
+    releaseInfo: {
+      tagCount: releases.tags ? releases.tags.length : 0,
+      lastRelease: releases.tags && releases.tags.length > 0
+        ? releases.tags[releases.tags.length - 1]
+        : null,
+      cadence: releases.cadence || null
+    },
+    commitShape: {
+      typicalSize: commitShape.typicalSize || null,
+      filesPerCommit: commitShape.filesPerCommit || null,
+      mergeCount: commitShape.mergeCount || 0
+    }
+  };
+}
+
+module.exports = {
+  collectGitData,
+  DEFAULT_OPTIONS
+};

lib/collectors/index.js

@@ -13,6 +13,7 @@ const github = require('./github');
 const documentation = require('./documentation');
 const codebase = require('./codebase');
 const docsPatterns = require('./docs-patterns');
+const git = require('./git');
 
 const DEFAULT_OPTIONS = {
   collectors: ['github', 'docs', 'code'],
@@ -50,7 +51,8 @@ function collect(options = {}) {
     github: null,
     docs: null,
     code: null,
-    docsPatterns: null
+    docsPatterns: null,
+    git: null
   };
 
   // Collect from each enabled collector
@@ -70,6 +72,10 @@ function collect(options = {}) {
     data.docsPatterns = docsPatterns.collect(opts);
   }
 
+  if (collectors.includes('git')) {
+    data.git = git.collectGitData(opts);
+  }
+
   return data;
 }
 
@@ -103,6 +109,7 @@ module.exports = {
   documentation,
   codebase,
   docsPatterns,
+  git,
 
   // Re-export commonly used functions for convenience
   scanGitHubState: github.scanGitHubState,
@@ -121,6 +128,8 @@ module.exports = {
   isInternalExport: docsPatterns.isInternalExport,
   isEntryPoint: docsPatterns.isEntryPoint,
 
+  collectGitData: git.collectGitData,
+
   // Constants
   DEFAULT_OPTIONS
 };