showcase: align inactivity condition and wording between SVG and gemtext

Both the rank-history SVG and the gemtext showcase now use the same rule:
  inactive = AvgCommitAge (last 42 commits on HEAD) > 730 days (~2 years)

Changes:
- SVG subtitle: 'no meaningful commits in 1+ years' → 'avg commit age > 2 years'
- SVG struct comment: updated to describe the 730-day/42-commit rule accurately
- gemtext: dropped the secondary 'lastCommit > 365 days' guard (it allowed
  projects like muttdelay to escape despite a single stray recent commit)
- gemtext notice text: 'Last meaningful activity was over 2 years ago' →
  'The average age of its last 42 commits exceeds 2 years'

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

2 files changed, 13 insertions, 15 deletions

diff --git a/internal/showcase/rank_history_svg.go b/internal/showcase/rank_history_svg.go
index 67281cb..aae4dc1 100644
--- a/internal/showcase/rank_history_svg.go
+++ b/internal/showcase/rank_history_svg.go
@@ -37,10 +37,11 @@ type svgTimePoint struct {
 }
 
 // svgProjectData carries per-project metadata used by the interactive JS layer.
-// Inactive is true when the project's average commit age exceeds 730 days AND
-// the last commit was over a year ago — matching the gemtext inactivity notice.
-// Inactive projects are rendered as grey lines by default and only switch to
-// their project colour when the user mouses over their legend entry.
+// Inactive is true when the project's average commit age (last 42 commits on
+// HEAD) exceeds 730 days (~2 years).  A single recent commit does not rescue
+// a dormant project; ~42 recent commits are needed to move the average below
+// the threshold.  Inactive projects are rendered as grey lines by default and
+// only switch to their project colour when the user mouses over their legend entry.
 type svgProjectData struct {
 	Name     string         `json:"name"`
 	Color    string         `json:"color"`
@@ -393,7 +394,7 @@ svg{background:#1a1a2e;font-family:monospace}
 		svgViewWidth/2, len(allProjects))
 	// Second subtitle: explain the grey lines so readers know what they mean.
 	fmt.Fprintf(&svg,
-		`<text class="sub" x="%d" y="57" text-anchor="middle">grey lines = inactive projects (no meaningful commits in 1+ years) · hover legend entry to highlight</text>`,
+		`<text class="sub" x="%d" y="57" text-anchor="middle">grey lines = inactive projects (avg commit age &gt; 2 years) · hover legend entry to highlight</text>`,
 		svgViewWidth/2)
 
 	// Rotated Y-axis label.
diff --git a/internal/showcase/showcase.go b/internal/showcase/showcase.go
index fbae2b7..4e8d637 100644
--- a/internal/showcase/showcase.go
+++ b/internal/showcase/showcase.go
@@ -1046,16 +1046,13 @@ func (g *Generator) formatGemtext(summaries []ProjectSummary) string {
 				builder.WriteString("* 🧪 Status: Experimental (no releases yet)\n")
 			}
 
-			// Check if project might be obsolete (avg age > 2 years AND last commit > 1 year)
-			if summary.Metadata.AvgCommitAge > 730 && summary.Metadata.LastCommitDate != "" {
-				// Parse the last commit date
-				lastCommit, err := time.Parse("2006-01-02", summary.Metadata.LastCommitDate)
-				if err == nil {
-					daysSinceLastCommit := time.Since(lastCommit).Hours() / 24
-					if daysSinceLastCommit > 365 {
-						builder.WriteString("\n⚠️  **Notice**: This project appears to be finished, obsolete, or no longer maintained. Last meaningful activity was over 2 years ago. Use at your own risk.")
-					}
-				}
+			// Mark as inactive when the average age of the last 42 commits exceeds
+			// 730 days (~2 years).  A single recent commit (e.g. a deprecation
+			// notice) does not rescue a dormant project — ~42 recent commits are
+			// required to move the average below the threshold.  This matches the
+			// grey-line rule used in the interactive rank-history SVG.
+			if summary.Metadata.AvgCommitAge > 730 {
+				builder.WriteString("\n⚠️  **Notice**: This project appears to be inactive or no longer maintained. The average age of its last 42 commits exceeds 2 years. Use at your own risk.")
 			}
 			builder.WriteString("\n\n")
 		}