docs: reorganize skills into pkm category and add crit skill

- Create new `pkm` directory for Personal Knowledge Management skills
- Move conversation-summary, knowledge-gardener, and research-vault from `personal` to `pkm`
- Add new crit skill for brainstorming with the CRIT framework
- Update skill descriptions for clarity and consistency
- Add audio-product-dsp, grilling, and research-engineering to model-invoked listings
- Update skill paths across README files to reflect new directory structure

common/pkm/research-vault/references/research-packet-template.md

@@ -0,0 +1,149 @@
+# Research Packet Template
+
+Use inside `Research/<YYYY-MM-DD> <Topic>/` unless the vault has a clearer convention.
+
+## Required files
+
+### `Index.md`
+
+```markdown
+# <Topic>
+
+## Purpose
+- Learning goal:
+- Scope:
+- Success criteria:
+
+## Main Takeaways
+-
+
+## Packet Map
+- [[Sources]]
+- [[Synthesis]]
+- [[Claims]]
+- [[Questions]]
+- [[Conversation]]
+- [[Glossaries]]
+
+## Related Vault Notes
+-
+
+## Open Questions
+-
+```
+
+### `Sources.md`
+
+```markdown
+# Sources
+
+| Source | Type | Why useful | Reliability notes | Accessed |
+|---|---|---|---|---|
+|  |  |  |  |  |
+
+## Notes
+-
+```
+
+Include source links, books, papers, docs, videos, examples, search terms, or relevant vault notes only when they improve learning or evidence quality.
+
+### `Synthesis.md`
+
+```markdown
+# Synthesis
+
+## Short Answer
+
+## Explanation
+
+## Examples
+
+## Disagreements or Uncertainty
+
+## Practical Implications
+
+## Links
+-
+```
+
+### `Claims.md`
+
+```markdown
+# Claims
+
+## Claim: <claim>
+- Evidence:
+- Source:
+- Confidence: high | medium | low
+- Implications:
+- Related notes:
+```
+
+### `Questions.md`
+
+```markdown
+# Questions
+
+## User Questions
+-
+
+## Open Questions
+-
+
+## Deferred or Out of Scope
+-
+
+## Follow-up Search Terms
+-
+```
+
+### `Conversation.md`
+
+```markdown
+# Conversation
+
+## Learning Goal
+
+## Assumptions
+
+## Understanding Checks
+
+## User Corrections
+
+## Decisions
+
+## Resources Shared
+-
+```
+
+Record important answers, corrections, and scope decisions as the session progresses.
+
+### `Glossaries.md`
+
+```markdown
+# Glossaries
+
+## <Term or Acronym>
+- Expansion:
+- Plain-language definition:
+- Domain/context:
+- Appeared in:
+- Related links:
+```
+
+Add every acronym, abbreviation, domain-specific phrase, specialized term, jargon term, and domain nomenclature encountered.
+
+## Atomic note
+
+```markdown
+# <Concept>
+
+## Idea
+
+## Why it matters
+
+## Evidence or source
+
+## Related notes
+-
+```