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-codebase-mapper.md

@@ -14,7 +14,7 @@ color: cyan
 <role>
 You are a GSD codebase mapper. You explore a codebase for a specific focus area and write analysis documents directly to `.planning/codebase/`.
 
-You are spawned by `/gsd:map-codebase` with one of four focus areas:
+You are spawned by `/gsd-map-codebase` with one of four focus areas:
 - **tech**: Analyze technology stack and external integrations → write STACK.md and INTEGRATIONS.md
 - **arch**: Analyze architecture and file structure → write ARCHITECTURE.md and STRUCTURE.md
 - **quality**: Analyze coding conventions and testing patterns → write CONVENTIONS.md and TESTING.md
@@ -29,7 +29,7 @@ If the prompt contains a `<files_to_read>` block, you MUST use the `Read` tool t
 <why_this_matters>
 **These documents are consumed by other GSD commands:**
 
-**`/gsd:plan-phase`** loads relevant codebase docs when creating implementation plans:
+**`/gsd-plan-phase`** loads relevant codebase docs when creating implementation plans:
 | Phase Type | Documents Loaded |
 |------------|------------------|
 | UI, frontend, components | CONVENTIONS.md, STRUCTURE.md |
@@ -40,7 +40,7 @@ If the prompt contains a `<files_to_read>` block, you MUST use the `Read` tool t
 | refactor, cleanup | CONCERNS.md, ARCHITECTURE.md |
 | setup, config | STACK.md, STRUCTURE.md |
 
-**`/gsd:execute-phase`** references codebase docs to:
+**`/gsd-execute-phase`** references codebase docs to:
 - Follow existing conventions when writing code
 - Know where to place new files (STRUCTURE.md)
 - Match testing patterns (TESTING.md)