fix: show contextual warning for dev installs with stale hooks (#2162)

When a user manually installs a dev branch where VERSION > npm latest,
gsd-check-update detects hooks as "stale" and the statusline showed
the red "⚠ stale hooks — run /gsd-update" message. Running /gsd-update
would incorrectly downgrade the dev install to the npm release.

Fix: detect dev install (cache.installed > cache.latest) in the
statusline and show an amber "⚠ dev install — re-run installer to sync
hooks" message instead, with /gsd-update reserved for normal upgrades.

Also expand the update.md workflow's installed > latest branch to
explain the situation and give the correct remediation command
(node bin/install.js --global --claude, not /gsd-update).

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

get-shit-done/workflows/update.md

@@ -289,7 +289,16 @@ Exit.
 **Installed:** X.Y.Z
 **Latest:** A.B.C
 
-You're ahead of the latest release (development version?).
+You're ahead of the latest release — this looks like a dev install.
+
+If you see a "⚠ dev install — re-run installer to sync hooks" warning in
+your statusline, your hook files are older than your VERSION file. Fix it
+by re-running the local installer from your dev branch:
+
+    node bin/install.js --global --claude
+
+Running /gsd-update would install the npm release (A.B.C) and downgrade
+your dev version — do NOT use it to resolve this warning.
 ```
 
 Exit.

hooks/gsd-statusline.js

@@ -211,7 +211,20 @@ function runStatusline() {
           gsdUpdate = '\x1b[33m⬆ /gsd-update\x1b[0m │ ';
         }
         if (cache.stale_hooks && cache.stale_hooks.length > 0) {
-          gsdUpdate += '\x1b[31m⚠ stale hooks — run /gsd-update\x1b[0m │ ';
+          // If installed version is ahead of npm latest, this is a dev install.
+          // Running /gsd-update would downgrade — show a contextual warning instead.
+          const isDevInstall = (() => {
+            if (!cache.installed || !cache.latest || cache.latest === 'unknown') return false;
+            const parseV = v => v.replace(/^v/, '').split('.').map(Number);
+            const [ai, bi, ci] = parseV(cache.installed);
+            const [an, bn, cn] = parseV(cache.latest);
+            return ai > an || (ai === an && bi > bn) || (ai === an && bi === bn && ci > cn);
+          })();
+          if (isDevInstall) {
+            gsdUpdate += '\x1b[33m⚠ dev install — re-run installer to sync hooks\x1b[0m │ ';
+          } else {
+            gsdUpdate += '\x1b[31m⚠ stale hooks — run /gsd-update\x1b[0m │ ';
+          }
         }
       } catch (e) {}
     }