fix(#2697): replace retired /gsd: prefix with /gsd- in all user-facing text (#2699)

All workflow, command, reference, template, and tool-output files that
surfaced /gsd:<cmd> as a user-typed slash command have been updated to
use /gsd-<cmd>, matching the Claude Code skill directory name.

Closes #2697

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

get-shit-done/workflows/map-codebase.md

@@ -29,8 +29,8 @@ Documents are reference material for Claude when planning/executing. Always incl
 
 <step name="parse_paths_flag" priority="first">
 Parse an optional `--paths <p1,p2,...>` argument. When supplied (by the
-post-execute codebase-drift gate in `/gsd:execute-phase` or by a user running
-`/gsd:map-codebase --paths apps/accounting,packages/ui`), the workflow
+post-execute codebase-drift gate in `/gsd-execute-phase` or by a user running
+`/gsd-map-codebase --paths apps/accounting,packages/ui`), the workflow
 operates in **incremental-remap mode**:
 
 - Pass `--paths <p1>,<p2>,...` through to each spawned `gsd-codebase-mapper`
@@ -413,12 +413,12 @@ Created .planning/codebase/:
 
 `/clear` then:
 
-`/gsd:new-project`
+`/gsd-new-project`
 
 ---
 
 **Also available:**
-- Re-run mapping: `/gsd:map-codebase`
+- Re-run mapping: `/gsd-map-codebase`
 - Review specific file: `cat .planning/codebase/STACK.md`
 - Edit any document before proceeding