docs: consolidate all docs under docs/ — single source of truth

Move issues (01–29) and PRD from .scratch/distributed-inference-network/
into docs/issues/ and docs/. Update ralph_progress.py DEFAULT_PRD path
and rewrite docs/agents/issue-tracker.md to reflect the new layout.

The distributed_inference_network.egg-info/docs/ mirror is a build
artifact already covered by *.egg-info/ in .gitignore — not committed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/agents/issue-tracker.md

@@ -1,18 +1,18 @@
 # Issue tracker: Local Markdown
 
-Issues and PRDs for this repo live as markdown files in `.scratch/`.
+Issues and PRDs for this project live as markdown files under `docs/`.
 
 ## Conventions
 
-- One feature per directory: `.scratch/<feature-slug>/`
-- The PRD is `.scratch/<feature-slug>/PRD.md`
-- Implementation issues are `.scratch/<feature-slug>/issues/<NN>-<slug>.md`, numbered from `01`
+- The PRD is `docs/PRD.md` (narrative) and `docs/prd.json` (machine-readable story list used by ralph)
+- Implementation issues (user stories) are `docs/issues/<NN>-<slug>.md`, numbered from `01`
 - Triage state is recorded as a `Status:` line near the top of each issue file (see `triage-labels.md` for the role strings)
+- ADRs (architecture decisions) are `docs/adr/<NNNN>-<slug>.md`, numbered from `0001`
 - Comments and conversation history append to the bottom of the file under a `## Comments` heading
 
 ## When a skill says "publish to the issue tracker"
 
-Create a new file under `.scratch/<feature-slug>/` (creating the directory if needed).
+Create a new file under `docs/issues/` following the numbering convention.
 
 ## When a skill says "fetch the relevant ticket"