fix: replace /gsd: slash command format with /gsd- skill format in all user-facing content (#1579)

* fix: replace /gsd: command format with /gsd- skill format in all suggestions

All next-step suggestions shown to users were still using the old colon
format (/gsd:xxx) which cannot be copy-pasted as skills. Migrated all
occurrences across agents/, commands/, get-shit-done/, docs/, README files,
bin/install.js (hardcoded defaults for claude runtime), and
get-shit-done/bin/lib/*.cjs (generate-claude-md templates and error messages).
Updated tests to assert new hyphen format instead of old colon format.

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

* fix: migrate remaining /gsd: format to /gsd- in hooks, workflows, and sdk

Addresses remaining user-facing occurrences missed in the initial migration:

- hooks/: fix 4 user-facing messages (pause-work, update, fast, quick)
  and 2 comments in gsd-workflow-guard.js
- get-shit-done/workflows/: fix 21 Skill() literal calls that Claude
  executes directly (installer does not transform workflow content)
- sdk/prompt-sanitizer.ts: update regex to strip /gsd- format in addition
  to legacy /gsd: format; update JSDoc comment
- tests/: update autonomous-ui-steps, prompt-sanitizer to assert new format

Note: commands/gsd/*.md frontmatter (name: gsd:xxx) intentionally unchanged
— installer derives skillName from directory path, not the name field.

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

* fix(plan-phase): preserve --chain flag in auto-advance sync and handle ui-phase gate in chain mode

Bug 1: step 15 sync-flag check only guarded against --auto, causing
_auto_chain_active to be cleared when plan-phase is invoked without
--auto in ARGUMENTS even though a --chain pipeline was active. Added
--chain to the guard condition, matching discuss-phase behaviour.

Bug 2: UI Design Contract gate (step 5.6) always exited the workflow
when UI-SPEC was missing, breaking the discuss --chain pipeline
silently. When _auto_chain_active is true, the gate now auto-invokes
gsd-ui-phase --auto via Skill() and continues to step 6 without
prompting. Manual invocations retain the existing AskUserQuestion flow.

* fix: remove <sub>/clear</sub> pattern and duplicate old-format command in discuss-phase.md

---------

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

agents/gsd-debugger.md

@@ -1,6 +1,6 @@
 ---
 name: gsd-debugger
-description: Investigates bugs using scientific method, manages debug sessions, handles checkpoints. Spawned by /gsd:debug orchestrator.
+description: Investigates bugs using scientific method, manages debug sessions, handles checkpoints. Spawned by /gsd-debug orchestrator.
 tools: Read, Write, Edit, Bash, Grep, Glob, WebSearch
 color: orange
 # hooks:
@@ -16,7 +16,7 @@ You are a GSD debugger. You investigate bugs using systematic scientific method,
 
 You are spawned by:
 
-- `/gsd:debug` command (interactive debugging)
+- `/gsd-debug` command (interactive debugging)
 - `diagnose-issues` workflow (parallel UAT diagnosis)
 
 Your job: Find the root cause through hypothesis testing, maintain debug file state, optionally fix and verify (depending on mode).
@@ -991,7 +991,7 @@ Gather symptoms through questioning. Update file after EACH answer.
   - Otherwise -> proceed to fix_and_verify
 - **ELIMINATED:** Append to Eliminated section, form new hypothesis, return to Phase 2
 
-**Context management:** After 5+ evidence entries, ensure Current Focus is updated. Suggest "/clear - run /gsd:debug to resume" if context filling up.
+**Context management:** After 5+ evidence entries, ensure Current Focus is updated. Suggest "/clear - run /gsd-debug to resume" if context filling up.
 </step>
 
 <step name="resume_from_file">