Add distributed server implementation and protocol definitions

- Introduced `protocol.py` for shared data models used in server/client communication, including request and response schemas for registration, job submission, and status updates.
- Implemented `server.py` to manage a SQLite job queue and client registry, handling job polling, status updates, and job completion.
- Created a cheat sheet for server usage, detailing commands for starting the server, submitting jobs, and monitoring clients.
- Added several experiment configuration files for various training setups, including geometry vector injections and baseline ensembles.

v4/distributed/server_cheat_sheet.md

@@ -0,0 +1,147 @@
+# Distributed Server Cheat Sheet
+
+All commands assume server is running on hades at port 8765.
+
+## Start Server
+```bash
+python -m v4.distributed.server --token hypertower
+```
+Run inside tmux so it survives disconnects:
+```bash
+tmux new -s htserver
+python -m v4.distributed.server --token hypertower
+# Ctrl-B D to detach
+tmux attach -t htserver   # reattach later
+```
+
+## Local Workflow (hades as server + client)
+
+```bash
+# Terminal 1 — server
+python -m v4.distributed.server --token hypertower
+
+# Terminal 2 — client (skip rsync, results already local)
+python -m v4.distributed.client \
+    --server http://hades:8765 --token hypertower \
+    --server-ssh ignored --server-path ignored \
+    --local-path /home/rpotter/hypertower \
+    --no-sync
+
+# Terminal 3 — dispatch (exits after queuing; client picks up jobs)
+python -m v4.distributed.batch_dispatch \
+    --server http://hades:8765 --token hypertower \
+    --config v4/configs/ensemble_fused.json \
+    --batch v4/scripts/experiments/my_batch.json
+```
+
+---
+
+## Start Clients
+
+**Hades (server-local, no sync):**
+```bash
+python -m v4.distributed.client \
+    --server http://hades:8765 --token hypertower \
+    --server-ssh ignored --server-path ignored \
+    --local-path /home/rpotter/hypertower \
+    --no-sync
+```
+
+**Apollo (remote client):**
+```bash
+python -m v4.distributed.client \
+    --server http://hades:8765 --token hypertower \
+    --server-ssh rpotter@hades \
+    --server-path /home/rpotter/hypertower \
+    --local-path /home/odin/hypertower
+```
+
+---
+
+## Monitoring
+
+**Live client monitor (refreshes every 5s):**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower clients --watch
+```
+
+**Faster refresh:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower clients --watch --interval 2
+```
+
+**Inspect a single client:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower clients <client_id>
+```
+
+**View job queue:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower jobs
+```
+
+**Filter by state:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower jobs --state pending
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower jobs --state running
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower jobs --state failed
+```
+
+---
+
+## Submitting Jobs
+
+**Batch dispatch (dry run first):**
+```bash
+python -m v4.distributed.batch_dispatch \
+    --server http://hades:8765 --token hypertower \
+    --config v4/configs/ensemble_fused.json \
+    --batch v4/scripts/experiments/fusion_dim_sweep.json \
+    --dry-run
+```
+
+**Live submit:**
+```bash
+python -m v4.distributed.batch_dispatch \
+    --server http://hades:8765 --token hypertower \
+    --config v4/configs/ensemble_fused.json \
+    --batch v4/scripts/experiments/fusion_dim_sweep.json
+```
+
+**Fewer reps (e.g. quick test):**
+```bash
+python -m v4.distributed.batch_dispatch \
+    --server http://hades:8765 --token hypertower \
+    --config v4/configs/ensemble_fused.json \
+    --batch v4/scripts/experiments/fusion_dim_sweep.json \
+    --reps 3
+```
+
+---
+
+## Queue Management
+
+**Clear failed jobs:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower clear --states failed
+```
+
+**Clear running jobs (orphan cleanup):**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower clear --states running
+```
+
+**Clear all jobs:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower clear --all
+```
+
+**Clear by run name:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower clear --run-name experiments/fusion_dim_sweep/dim256
+```
+
+**Cancel a specific job:**
+```bash
+python -m v4.distributed.cli --server http://hades:8765 --token hypertower cancel <job_id>
+```