Document agent skills and repository context sources

AGENTS.md

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+
+## Agent skills
+
+### Issue tracker
+
+Issues and specs for this repo live as markdown files under `.scratch/`. See `docs/agents/issue-tracker.md`.
+
+### Domain docs
+
+This is a single-context repo. Domain context lives in root `CONTEXT.md` when present, and architectural decisions live in `docs/adr/`. See `docs/agents/domain.md`.

docs/agents/domain.md

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+# Domain Docs
+
+Before exploring a topic, read `CONTEXT.md` at the repo root when it exists, then read the relevant ADRs under `docs/adr/`.
+
+Missing context files should be ignored silently. Create `CONTEXT.md` lazily only when domain terminology or a durable decision needs to be recorded.
+
+## File structure
+
+This repository uses a single-context layout:
+
+```text
+/
+├── CONTEXT.md
+├── docs/adr/
+└── src/
+```
+
+## Vocabulary
+
+Use the project's established domain terms in issue titles, proposals, tests, and documentation. If a term is unclear or missing, treat it as a signal to clarify the domain model rather than inventing a synonym.
+
+## ADR conflicts
+
+If a proposal contradicts an existing ADR, call out the conflict explicitly instead of silently overriding it.

docs/agents/issue-tracker.md

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+# Issue tracker: Local Markdown
+
+Issues and specs for this repo live as markdown files in `.scratch/`.
+
+## Conventions
+
+- One feature per directory: `.scratch/<feature-slug>/`
+- The spec is `.scratch/<feature-slug>/spec.md`
+- Implementation issues are one file per ticket at `.scratch/<feature-slug>/issues/<NN>-<slug>.md`, numbered from `01`.
+- A ticket may include a `Status:` line near the top, using a simple project-defined state such as `open`, `in-progress`, `blocked`, or `done`.
+- Comments and conversation history append to the bottom under a `## Comments` heading.
+
+## When a skill says "publish to the issue tracker"
+
+Create a new file under `.scratch/<feature-slug>/`.
+
+## When a skill says "fetch the relevant ticket"
+
+Read the referenced markdown path.