showcase: activity check uses all-branch last-commit date to avoid false inactivity

Problem: projects with active development on a non-default branch (e.g. all
recent work on 'master' while the workdir HEAD is on 'screenshots') were
being greyed out in the rank-history SVG despite recent commits.

Fix:
- Add LastActivityDate string to RepoMetadata, computed with
  'git log --all -1 --pretty=format:%ai' (all local branches, no fetch).
  Code stats (AvgCommitAge, CommitCount, LOC, score) remain HEAD-only per
  the configured-branch rules.
- SVG inactivity check uses LastActivityDate (falling back to LastCommitDate
  if the field is absent in older cache entries).
- getLastActivityDate() added to metadata.go alongside getLastCommitDate().

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

2 files changed, 62 insertions, 22 deletions

diff --git a/internal/showcase/metadata.go b/internal/showcase/metadata.go
index 038dc08..c6c756b 100644
--- a/internal/showcase/metadata.go
+++ b/internal/showcase/metadata.go
@@ -22,20 +22,21 @@ type LanguageStats struct {
 
 // RepoMetadata holds metadata about a repository
 type RepoMetadata struct {
-	Languages       []LanguageStats // Programming languages with usage statistics
-	Documentation   []LanguageStats // Documentation/text files with usage statistics
-	CommitCount     int
-	LinesOfCode     int // Lines of code (excluding documentation)
-	LinesOfDocs     int // Lines of documentation
-	FirstCommitDate string
-	LastCommitDate  string
-	License         string
-	AvgCommitAge    float64 // Average age of last 42 commits in days
-	TagCount        int     // Total number of git tags in the repository
-	Score           float64 // Project score combining recent activity, reduced LOC weight, tag count, and release status
-	LatestTag       string  // Latest version tag (empty if no tags)
-	LatestTagDate   string  // Date of the latest tag (empty if no tags)
-	HasReleases     bool    // Whether the project has any releases/tags
+	Languages        []LanguageStats // Programming languages with usage statistics
+	Documentation    []LanguageStats // Documentation/text files with usage statistics
+	CommitCount      int
+	LinesOfCode      int // Lines of code (excluding documentation)
+	LinesOfDocs      int // Lines of documentation
+	FirstCommitDate  string
+	LastCommitDate   string
+	LastActivityDate string  // Most recent commit on any local branch (--all); used for activity checks
+	License          string
+	AvgCommitAge     float64 // Average age of last 42 commits in days (HEAD only; used for score)
+	TagCount         int     // Total number of git tags in the repository
+	Score            float64 // Project score combining recent activity, reduced LOC weight, tag count, and release status
+	LatestTag        string  // Latest version tag (empty if no tags)
+	LatestTagDate    string  // Date of the latest tag (empty if no tags)
+	HasReleases      bool    // Whether the project has any releases/tags
 }
 
 // extractRepoMetadata extracts metadata from a repository
@@ -83,6 +84,18 @@ func extractRepoMetadata(repoPath string) (*RepoMetadata, error) {
 	}
 	metadata.LastCommitDate = lastDate
 
+	// LastActivityDate is the most recent commit across ALL local branches so
+	// that projects with active development on non-default branches (e.g. a
+	// "develop" branch while HEAD is an old "master") are not falsely marked
+	// inactive.  Code stats (LOC, AvgCommitAge, score) remain HEAD-only per
+	// the configured branch rules.
+	activityDate, err := getLastActivityDate(repoPath)
+	if err != nil {
+		fmt.Printf("Warning: Failed to get last activity date: %v\n", err)
+		activityDate = lastDate // fall back to HEAD-based date
+	}
+	metadata.LastActivityDate = activityDate
+
 	// Check for license file
 	license := detectLicense(repoPath)
 	metadata.License = license
@@ -214,6 +227,25 @@ func getLastCommitDate(repoPath string) (string, error) {
 	return "", fmt.Errorf("no commits found")
 }
 
+// getLastActivityDate returns the date of the most recent commit across all
+// local branches (--all).  This is intentionally local-only: no network
+// fetch is performed, so it reflects the state of the last sync.  It is used
+// solely for the inactivity check (greying in the rank-history SVG) so that
+// projects with active work on non-default branches are not falsely flagged.
+// Code stats (LOC, AvgCommitAge, score) remain HEAD-only as per config.
+func getLastActivityDate(repoPath string) (string, error) {
+	cmd := exec.Command("git", "-C", repoPath, "log", "--all", "-1", "--pretty=format:%ai")
+	output, err := cmd.Output()
+	if err != nil {
+		return "", err
+	}
+	parts := strings.Fields(string(output))
+	if len(parts) > 0 {
+		return parts[0], nil
+	}
+	return "", fmt.Errorf("no commits found across all branches")
+}
+
 // detectLicense checks for common license files
 func detectLicense(repoPath string) string {
 	licenseFiles := []string{
diff --git a/internal/showcase/rank_history_svg.go b/internal/showcase/rank_history_svg.go
index 7a0386d..5022cd3 100644
--- a/internal/showcase/rank_history_svg.go
+++ b/internal/showcase/rank_history_svg.go
@@ -207,15 +207,23 @@ func GenerateRankHistorySVG(summaries []ProjectSummary) string {
 			continue // skip projects that have never appeared in any snapshot
 		}
 
-		// Mirror the inactivity check from formatGemtext: avg commit age > 730 days
-		// AND the most recent commit was also over a year ago.  Inactive projects
-		// are still drawn but as grey lines so they do not compete visually with
-		// active ones; they turn coloured only on legend-entry hover.
+		// A project is inactive when its average commit age (HEAD) exceeds 730
+		// days AND no commit on ANY local branch is younger than 365 days.
+		// Using LastActivityDate (all-branches) avoids false positives for
+		// projects whose default branch is old but development continues on
+		// another branch (e.g. a "develop" or "master" branch).
+		// Code stats (AvgCommitAge, score) remain HEAD-only per config rules.
 		inactive := false
-		if s.Metadata != nil && s.Metadata.AvgCommitAge > 730 && s.Metadata.LastCommitDate != "" {
-			if last, err := time.Parse("2006-01-02", s.Metadata.LastCommitDate); err == nil {
-				if time.Since(last).Hours()/24 > 365 {
-					inactive = true
+		if s.Metadata != nil && s.Metadata.AvgCommitAge > 730 {
+			activityDate := s.Metadata.LastActivityDate
+			if activityDate == "" {
+				activityDate = s.Metadata.LastCommitDate // fallback if field absent
+			}
+			if activityDate != "" {
+				if last, err := time.Parse("2006-01-02", activityDate); err == nil {
+					if time.Since(last).Hours()/24 > 365 {
+						inactive = true
+					}
 				}
 			}
 		}