feat: add /setup_docs, /reset, /expand commands and /upskill skill

Adds four contributions from @Michael-Bach:

- /setup_docs - document-driven profile population from a documents/ folder (CV, LinkedIn export, diplomas, references, past applications). Idempotent merge with explicit additive vs. conflicting buckets and per-conflict prompts.
- /reset - typed-RESET confirmation gate for clearing profile data and/or documents folder contents.
- /expand - additive competency enrichment from documents and public URLs already in the profile (GitHub repos, portfolio sites), with web-searched syllabus lookups for named courses and certifications.
- /upskill - skill-gap analysis vs tracked jobs (or single URL), produces a prioritized heatmap and learning plan with year-tagged WebSearch queries.

Also adds the documents/ folder convention with README and gitignore entries for personal output files.

Closes #6

.claude/settings.local.json

@@ -5,7 +5,7 @@
       "Bash(python3:*)",
       "Bash(python:*)",
       "Bash(curl:*)",
-      "Bash(bun:*)"
+      "Bash(bun:*)",
     ]
   }
 }