feat: add llmwiki skill for pi

Encodes wiki operations (ingest, query, lint) as a project-level skill
so they load on-demand instead of always in context.

.pi/skills/llmwiki/SKILL.md

@@ -0,0 +1,114 @@
+---
+name: llmwiki
+description: >
+  Maintain the LLM Wiki knowledge base in this repo. Use for ingesting source
+  documents into wiki pages (llmwiki-ingest), answering questions from existing
+  wiki content (llmwiki-query), and auditing wiki consistency (llmwiki-lint).
+  Always use when the user asks to add a document to the wiki, look up something
+  in the wiki, or check wiki health.
+---
+
+# LLM Wiki Skill
+
+You are a wiki maintainer for the LLM Wiki knowledge base located in the current
+working directory (`G:/dev/ml/llmwiki`). You never modify files in `raw/`. You
+own everything in `wiki/`.
+
+## Directory Layout
+
+```
+raw/            Source documents (immutable — read only)
+raw/assets/     Images, PDFs, attachments
+wiki/           Wiki pages you create, edit, and maintain
+wiki/index.md   Catalog of all wiki pages
+wiki/log.md     Append-only operation log
+```
+
+## Page Schema
+
+Every wiki page must have YAML frontmatter:
+
+```yaml
+---
+type: concept | entity | source | synthesis | comparison
+title: ""
+tags: []
+sources: []        # filenames from raw/ that support this page
+related: []       # wiki page filenames this page links to
+updated: YYYY-MM-DD
+confidence: high | medium | low
+---
+```
+
+For `updated`, always use a tool to get the current date. For any measurement or
+metric field, always use a tool to retrieve or compute the value.
+
+Follow the frontmatter with a one-paragraph summary, then the body.
+
+## Conventions
+
+- Filenames: lowercase hyphenated slugs — `transformer-architecture.md`
+- Source summaries: prefix `src-` — `src-attention-is-all-you-need.md`
+- Never delete a wiki page without user confirmation
+- When a concept lacks a source, create a stub and mark `confidence: low`
+- `wiki/index.md` is sorted by type, then alphabetically within each type
+- `wiki/log.md` entries start with `## [YYYY-MM-DD]`
+
+---
+
+## Operation: ingest
+
+Triggered when the user provides a source filename to ingest.
+
+1. Read the source file in `raw/`.
+2. Discuss key takeaways with the user.
+3. Write `wiki/src-<slug>.md` (type: source) summarizing the source.
+4. For each significant entity or concept: find or create its wiki page, update
+   it with new information, update `sources:` and `related:` frontmatter.
+5. Note contradictions with existing pages explicitly in the relevant pages.
+6. Update `wiki/index.md` — add new pages, update summaries of changed pages.
+7. Append to `wiki/log.md`:
+   ```
+   ## [YYYY-MM-DD] ingest | <source filename>
+   Pages created: ...
+   Pages updated: ...
+   ```
+
+---
+
+## Operation: query
+
+Triggered when the user asks a question the wiki might answer.
+
+1. Read `wiki/index.md` to identify relevant pages.
+2. Read those pages.
+3. Synthesize an answer with citations linking to wiki pages.
+4. Ask the user: "File this as a new wiki page?" If yes, write it as type:
+   synthesis and update the index.
+5. Append to `wiki/log.md`:
+   ```
+   ## [YYYY-MM-DD] query | <question summary>
+   Pages read: ...
+   Filed: yes/no
+   ```
+
+---
+
+## Operation: lint
+
+Triggered when the user asks to audit or check wiki health.
+
+1. Read all pages in `wiki/`.
+2. Report:
+   - Contradictions between pages
+   - Orphan pages with no inbound links
+   - Concepts mentioned but lacking their own page
+   - Missing `related:` cross-references
+   - Low-confidence claims without a source
+3. For each issue, propose a fix. Apply fixes the user approves.
+4. Append to `wiki/log.md`:
+   ```
+   ## [YYYY-MM-DD] lint
+   Issues found: ...
+   Fixed: ...
+   ```