fix(skill-author): fail loudly when scaffold repair cannot substitute

Why: repair_placeholders ran inside a command substitution, so a failing
sed left an emptied file behind and the script still exited 0 reporting
success.

- write via tmp file and abort on sed or mv failure
- re-check the target before moving staging into place
- stage in a dot-prefixed mktemp dir so a killed run leaves no fake skill
- source apm claims in deployment-modes.md; tag untyped code blocks

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KkT7RSDwDbmrM9T34b6sTi

plugins/kyberforge/.apm/skills/skill-author/references/sources.md

@@ -7,6 +7,7 @@ source_keys:
   - agentskills-evaluating-skills
   - agentskills-using-scripts
   - agentskills-quickstart
+  - apm-docs-llms-full
 ---
 
 # Sources
@@ -68,3 +69,11 @@ source_keys:
 - **Description:** Step-by-step guide to creating a first skill (roll-dice example), how discovery/activation/execution work in practice
 - **Contributing files:** SKILL.md, references/create.md
 - **Status:** `extracted`
+
+## apm-docs-llms-full
+
+- **URL:** https://microsoft.github.io/apm/llms-full.txt
+- **Research doc:** plugins/kyberforge/docs/research/docs/microsoft-apm/sources.md
+- **Description:** Published apm docs bundle — `apm compile` producing per-target output from an `apm.yml` package, the target-neutral `${PLUGIN_ROOT}` hook token apm rewrites per target, and hooks as primitives under `.apm/hooks/`
+- **Contributing files:** references/deployment-modes.md
+- **Status:** `extracted`