fix(3683): normalize /gsd:<cmd> → /gsd-<cmd> in command, workflow, and reference bodies (#3685)

* fix(3683): normalize /gsd:<cmd> → /gsd-<cmd> in command, workflow, and reference bodies

Extends #3677's agent-body normalizer to all body text staged through
copyWithPathReplacement (commands, workflows, references). The initial
isCommand guard was structurally redundant — normalizeAgentBodyForRuntime
already self-gates on shouldNormalizeHyphenNamespaceInAgentBody(runtime),
so dropping it covers all hyphen-name runtimes (Claude / Qwen / Hermes)
without affecting colon-canonical runtimes (Gemini).

Addresses the user-visible symptom in #3683: workflows like
get-shit-done/workflows/discuss-phase.md (7 colon refs) leaked /gsd:<cmd>
markers to the model context, which the model echoed at the end of
/gsd-discuss-phase runs.

Source-prose drift caught by the new cross-reference invariant test:

  - commands/gsd/plan-phase.md: removed a slash-form mention of the
    deleted /gsd-research-phase command (#3042)
  - commands/gsd/profile-user.md: replaced a slash-form artifact
    reference with a backticked bare name (the referenced item is a
    skill config, not a user-callable slash command)

Tests:

  - tests/bug-3683-command-colon-namespace-leak.test.cjs — runtime-form
    regression for commands/gsd/*.md staging
  - tests/bug-3683-command-cross-reference-invariant.test.cjs — locks
    cross-reference coherence: every /gsd-X / /gsd:X reference in a
    command body must resolve to commands/gsd/X.md (so a future rename
    forces every cross-reference to update)
  - tests/bug-3683-workflow-colon-namespace-leak.test.cjs — runtime-form
    regression for workflows + references; negative test for gemini
    asserting the colon form is preserved

Fixes #3683

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* docs(changeset): remove undefined cycle reference

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Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>